Realising the potential of Magnesium(Mg),several globally leading ventures have invested in the Mg industry,but their relatively poor corrosion resistance is a never ending saga till date.The corrosion and bio-corrosi...Realising the potential of Magnesium(Mg),several globally leading ventures have invested in the Mg industry,but their relatively poor corrosion resistance is a never ending saga till date.The corrosion and bio-corrosion behaviour of Mg has gained research attention and still remains a hot topic in the application of automobile,aerospace and biomedical industries.The intrinsic high electrochemical nature of Mg limits their utilization in diverse application.This scenario has prompted the development of Mg composites with an aim to achieve superior corrosion and bio-corrosion resistance.The present review enlightens the influence of grain size(GS),secondary phase,texture,type of matrix and reinforcement on the corrosion and bio-corrosion behaviour of Mg composites.Firstly,the corrosion and bio-corrosion behaviour of Mg composites manufactured by primary and secondary processing routes are elucidated.Secondly,the comprehensive corrosion and bio-corrosion mechanisms of these Mg composites are proposed.Thirdly,the individual role of GS,texture and corrosive medium on corrosion and bio-corrosion behaviour of Mg composites are clarified and revealed.The challenges encountered,unanswered issues in this field are explained in detail and accordingly the scope for future research is framed.The review is presented from basic concrete background to advanced corrosion mechanisms with an aim of creating interest among the readers like students,researchers and industry experts from various research backgrounds.Indeed,the corrosion and bio-corrosion behaviour of Mg composites are critically reviewed for the first time to:(i)contribute to the body of knowledge,(ii)foster research and development,(iii)make breakthrough,and(iv)create life changing innovations in the field of Mg composite corrosion.展开更多
Laser powder bed fusion(L-PBF)of Mg alloys has provided tremendous opportunities for customized production of aeronautical and medical parts.Layer thickness(LT)is of great significance to the L-PBF process but has not...Laser powder bed fusion(L-PBF)of Mg alloys has provided tremendous opportunities for customized production of aeronautical and medical parts.Layer thickness(LT)is of great significance to the L-PBF process but has not been studied for Mg alloys.In this study,WE43 Mg alloy bulk cubes,porous scaffolds,and thin walls with layer thicknesses of 10,20,30,and 40μm were fabricated.The required laser energy input increased with increasing layer thickness and was different for the bulk cubes and porous scaffolds.Porosity tended to occur at the connection joints in porous scaffolds for LT40 and could be eliminated by reducing the laser energy input.For thin wall parts,a large overhang angle or a small wall thickness resulted in porosity when a large layer thicknesses was used,and the porosity disappeared by reducing the layer thickness or laser energy input.A deeper keyhole penetration was found in all occasions with porosity,explaining the influence of layer thickness,geometrical structure,and laser energy input on the porosity.All the samples achieved a high fusion quality with a relative density of over 99.5%using the optimized laser energy input.The increased layer thickness resulted to more precipitation phases,finer grain sizes and decreased grain texture.With the similar high fusion quality,the tensile strength and elongation of bulk samples were significantly improved from 257 MPa and 1.41%with the 10μm layer to 287 MPa and 15.12%with the 40μm layer,in accordance with the microstructural change.The effect of layer thickness on the compressive properties of porous scaffolds was limited.However,the corrosion rate of bulk samples accelerated with increasing the layer thickness,mainly attributed to the increased number of precipitation phases.展开更多
More than 4600 papers in the field of Mg and Mg alloys were published and indexed in the Web of Science(WoS)Core Collection database in 2022.The bibliometric analyses indicate that the microstructure,mechanical proper...More than 4600 papers in the field of Mg and Mg alloys were published and indexed in the Web of Science(WoS)Core Collection database in 2022.The bibliometric analyses indicate that the microstructure,mechanical properties,and corrosion of Mg alloys are still the main research focus.Bio-Mg materials,Mg ion batteries and hydrogen storage Mg materials have attracted much attention.Notable contributions to the research and development of magnesium alloys were made by Chongqing University(>200 papers),Chinese Academy of Sciences,Shanghai Jiao Tong University,and Northeastern University(>100 papers)in China,Helmholtz Zentrum Hereon in Germany,Ohio State University in the USA,the University of Queensland in Australia,Kumanto University in Japan,and Seoul National University in Korea,University of Tehran in Iran,and National University of Singapore in Singapore,etc.This review is aimed to summarize the progress in the development of structural and functional Mg and Mg alloys in 2022.Based on the issues and challenges identified here,some future research directions are suggested.展开更多
Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical properties.The incorporation of rare earth(RE)elements,wit...Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical properties.The incorporation of rare earth(RE)elements,with their distinct physical and chemical properties,has greatly contributed to enhancing the mechanical performance,degradation behavior,and biological performance of biomedical Mg alloys.Currently,a series of RE-Mg alloys are being designed and investigated for orthopedic implants and cardiovascular stents,achieving substantial and encouraging research progress.In this work,a comprehensive summary of the state-of-the-art in biomedical RE-Mg alloys is provided.The physiological effects and design standards of RE elements in biomedical Mg alloys are discussed.Particularly,the degradation behavior and mechanical properties,including their underlying action are studied in-depth.Furthermore,the preparation techniques and current application status of RE-Mg alloys are reviewed.Finally,we address the ongoing challenges and propose future prospects to guide the development of high-performance biomedical Mg-RE alloys.展开更多
The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the...The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the two-color pyrometer technique,and the chemical composition of solid combustion residues were analyzed.The experimental results showed that the average flame propagation velocities of 23μm,40μm,60μm and 103μm MgH_(2)dust clouds in the stable propagation stage were 3.7 m/s,2.8 m/s,2.1 m/s and 0.9 m/s,respectively.The dust clouds with smaller particle sizes had faster flame propagation velocity and stronger oscillation intensity,and their flame temperature distributions were more even and the temperature gradients were smaller.The flame structures of MgH_(2)dust clouds were significantly affected by the particle sinking velocity,and the combustion processes were accompanied by micro-explosion of particles.The falling velocities of 23μm and 40μm MgH_(2)particles were 2.24 cm/s and 6.71 cm/s,respectively.While the falling velocities of 60μm and 103μm MgH_(2)particles were as high as 15.07 cm/s and 44.42 cm/s,respectively,leading to a more rapid downward development and irregular shape of the flame.Furthermore,the dehydrogenation reaction had a significant effect on the combustion performance of MgH_(2)dust.The combustion of H_(2)enhanced the ignition and combustion characteristics of MgH_(2)dust,resulting in a much higher explosion power than the pure Mg dust.The micro-structure characteristics and combustion residues composition analysis of MgH_(2)dust indicated that the combustion control mechanism of MgH_(2)dust flame was mainly the heterogeneous reaction,which was affected by the dehydrogenation reaction.展开更多
This study offers significant insights into the multi-physics phenomena of the SLM process and the subsequent porosity characteristics of ZK60 Magnesium(Mg)alloys.High-speed in-situ monitoring was employed to visualis...This study offers significant insights into the multi-physics phenomena of the SLM process and the subsequent porosity characteristics of ZK60 Magnesium(Mg)alloys.High-speed in-situ monitoring was employed to visualise process signals in real-time,elucidating the dynamics of melt pools and vapour plumes under varying laser power conditions specifically between 40 W and 60 W.Detailed morphological analysis was performed using Scanning-Electron Microscopy(SEM),demonstrating a critical correlation between laser power and pore formation.Lower laser power led to increased pore coverage,whereas a denser structure was observed at higher laser power.This laser power influence on porosity was further confirmed via Optical Microscopy(OM)conducted on both top and cross-sectional surfaces of the samples.An increase in laser power resulted in a decrease in pore coverage and pore size,potentially leading to a denser printed part of Mg alloy.X-ray Computed Tomography(XCT)augmented these findings by providing a 3D volumetric representation of the sample internal structure,revealing an inverse relationship between laser power and overall pore volume.Lower laser power appeared to favour the formation of interconnected pores,while a reduction in interconnected pores and an increase in isolated pores were observed at higher power.The interplay between melt pool size,vapour plume effects,and laser power was found to significantly influence the resulting porosity,indicating a need for effective management of these factors to optimise the SLM process of Mg alloys.展开更多
Hydrogen energy has emerged as a pivotal solution to address the global energy crisis and pave the way for a cleaner,low-carbon,secure,and efficient modern energy system.A key imperative in the utilization of hydrogen...Hydrogen energy has emerged as a pivotal solution to address the global energy crisis and pave the way for a cleaner,low-carbon,secure,and efficient modern energy system.A key imperative in the utilization of hydrogen energy lies in the development of high-performance hydrogen storage materials.Magnesium-based hydrogen storage materials exhibit remarkable advantages,including high hydrogen storage density,cost-effectiveness,and abundant magnesium resources,making them highly promising for the hydrogen energy sector.Nonetheless,practical applications of magnesium hydride for hydrogen storage face significant challenges,primarily due to their slow kinetics and stable thermodynamic properties.Herein,we briefly summarize the thermodynamic and kinetic properties of MgH2,encompassing strategies such as alloying,nanoscaling,catalyst doping,and composite system construction to enhance its hydrogen storage performance.Notably,nanoscaling and catalyst doping have emerged as more effective modification strategies.The discussion focuses on the thermodynamic changes induced by nanoscaling and the kinetic enhancements resulting from catalyst doping.Particular emphasis lies in the synergistic improvement strategy of incorporating nanocatalysts with confinement materials,and we revisit typical works on the multi-strategy optimization of MgH2.In conclusion,we conduct an analysis of outstanding challenges and issues,followed by presenting future research and development prospects for MgH2 as hydrogen storage materials.展开更多
Magnesium and magnesium alloy foils have great potential for application in battery anodes,electromagnetic shielding,optics and acoustics,and biology because of their excellent specific damping,internal dissipation co...Magnesium and magnesium alloy foils have great potential for application in battery anodes,electromagnetic shielding,optics and acoustics,and biology because of their excellent specific damping,internal dissipation coefficients,magnetic and electrical conductivities,as well as high theoretical specific capacity.However,magnesium alloys exhibit poor deformation ability due to their hexagonal close-packed crystal structure.Preparing magnesium and magnesium alloy foils with thicknesses of less than 0.1 mm is difficult because of surface oxidation and grain growth at high temperatures or severe anisotropy after cold rolling that leads to cracks.Numerous methods have been applied to prepare magnesium alloy foils.They include warm rolling,cold rolling,accumulative roll bonding,electric plastic rolling,and on-line heating rolling.Defects of magnesium and magnesium alloy foils during preparation,such as edge cracks and breakage,are important factors for consideration.Herein,the current status of the research on magnesium and magnesium alloy foils is summarized from the aspects of foil preparation,defect control,performance characterization,and application prospects.The advantages and disadvantages of different preparation methods and defect(edge cracks and breakage)mechanisms in the preparation of foils are identified.展开更多
Nonunion represents a crucial challenge in orthopedic medicine,demanding innovative solutions beyond the scope of traditional bone grafting methods.Among the various strategies available,magnesium(Mg)implants have bee...Nonunion represents a crucial challenge in orthopedic medicine,demanding innovative solutions beyond the scope of traditional bone grafting methods.Among the various strategies available,magnesium(Mg)implants have been recognized for their biocompatibility and biodegradability.However,their susceptibility to rapid corrosion and degradation has garnered notable research interest in bone tissue engineering(BTE),particularly in the development of Mg-incorporated biocomposite scaffolds.These scaffolds gradually release Mg2+,which enhances immunomodulation,osteogenesis,and angiogenesis,thus facilitating effective bone regeneration.This review presents myriad fabrication techniques used to create Mg-incorporated biocomposite scaffolds,including electrospinning,three-dimensional printing,and sol-gel synthesis.Despite these advancements,the application of Mg-incorporated biocomposite scaffolds faces challenges such as controlling the degradation rate of Mg and ensuring mechanical stability.These limitations highlight the necessity for ongoing research aimed at refining fabrication techniques to better regulate the physicochemical and osteogenic properties of scaffolds.This review provides insights into the potential of Mg-incorporated biocomposite scaffolds for BTE and the challenges that need to be addressed for their successful translation into clinical applications.展开更多
The lignite-derived carbon from self-protection pyrolysis was employed to balance the fracturing and cold-welding of magnesium during ball milling.Particle size analysis indicates that the introduction of lignite-deri...The lignite-derived carbon from self-protection pyrolysis was employed to balance the fracturing and cold-welding of magnesium during ball milling.Particle size analysis indicates that the introduction of lignite-derived carbon can effectively reduce the particle size of Mg while the introduction of graphite does no help.Besides,the effect of lignite-derived carbon on crystallite size reduction of Mg is also better than graphite.A moderate cold-welding phenomenon was observed after ball-milling Mg with the lignite-derived carbon,suggesting less Mg is wasted on the milling vials and balls.Molecular dynamic simulations reveal that the balanced fracturing and cold-welding of magnesium during ball milling is mainly attributed to the special structure of the lignite-derived carbon:graphitized short-range ordered stacking function as dry lubricant and irregular shape/sharp edge function as milling aid.The preliminary findings in current study are expected to offer implications for designing efficient Mg-based hydrogen storage materials.展开更多
Metal-air battery is an environmental friendly energy storage system with unique open structure.Magnesium(Mg)and its alloys have been extensively attempted as anodes for air batteries due to high theoretical energy de...Metal-air battery is an environmental friendly energy storage system with unique open structure.Magnesium(Mg)and its alloys have been extensively attempted as anodes for air batteries due to high theoretical energy density,low cost,and recyclability.However,the study on Mg-air battery(MAB)is still at the laboratory level currently,mainly owing to the low anodic efficiency caused by the poor corrosion resistance.In order to reduce corrosion losses and achieve optimal utilization efficiency of Mg anode,the design strategies are reviewed from microstructure perspectives.Firstly,the corrosion behaviors have been discussed,especially the negative difference effect derived by hydrogen evolution.Special attention is given to the effect of anode micro-structures on the MAB,which includes grain size,grain orientation,second phases,crystal structure,twins,and dislocations.For further improvement,the discharge performance,long period stacking ordered phase and its enhancing effect are considered.Meanwhile,given the current debates over Mg dendrites,the potential risk,the impact on discharge,and the elimination strategies are discussed.Microstructure control and single crystal would be promising ways for MAB anode.展开更多
This review focuses on thermodynamic and physical parameters,synthesis methods,and reported phases of Magnesium(Mg)containing high-entropy alloys(HEAs).Statistical data of publications concerning Mg-containing HEAs we...This review focuses on thermodynamic and physical parameters,synthesis methods,and reported phases of Magnesium(Mg)containing high-entropy alloys(HEAs).Statistical data of publications concerning Mg-containing HEAs were collected and analyzed.Data on the chemical elements included in Mg-containing HEAs,their theoretical end experimental densities,thermodynamic parameters,physical parameters,fabricated techniques and reported phases were also collected and discussed.On the basis of this information,a new classification for HEAs was proposed.It is also shown that the existing thermodynamic parameters cannot accurately predict the formation of a single phase solid solution for Mg-containing HEAs.The physical parameters of Mg-containing HEAs are within a wide range,and most of the synthesized Mg-containing HEAs have a complex multiphase structure.展开更多
Electric arc furnace(EAF)dust is an important secondary resource containing metals,such as zinc(Zn)and iron(Fe).Recover-ing Zn from EAF dust can contribute to resource recycling and reduce environmental impacts.Howeve...Electric arc furnace(EAF)dust is an important secondary resource containing metals,such as zinc(Zn)and iron(Fe).Recover-ing Zn from EAF dust can contribute to resource recycling and reduce environmental impacts.However,the high chemical stability of ZnFe_(2)O_(4)in EAF dust poses challenges to Zn recovery.To address this issue,a facile approach that involves oxygen-assisted chlorination using molten MgCl_(2)is proposed.This work focused on elucidating the role of O2 in the reaction between ZnFe_(2)O_(4)and molten MgCl_(2).The results demonstrate that MgCl_(2)effectively broke down the ZnFe_(2)O_(4)structure,and the high O2 atmosphere considerably promoted the sep-aration of Zn from other components in the form of ZnCl_(2).The presence of O2 facilitated the formation of MgFe_(2)O_(4),which stabilized Fe and prevented its chlorination.Furthermore,the excessive use of MgCl_(2)resulted in increased evaporation loss,and high temperatures pro-moted the rapid separation of Zn.Building on these findings,we successfully extracted ZnCl_(2)-enriched volatiles from practical EAF dust through oxygen-assisted chlorination.Under optimized conditions,this method achieved exceptional Zn chlorination percentage of over 97%within a short period,while Fe chlorination remained below 1%.The resulting volatiles contained 85wt%of ZnCl_(2),which can be further processed to produce metallic Zn.The findings offer guidance for the selective recovery of valuable metals,particularly from solid wastes such as EAF dust.展开更多
Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based stents.Nevertheless,the steps for preparing comp...Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based stents.Nevertheless,the steps for preparing composite coatings are usually complicated and time-consuming.Herein,a novel composite coating,composed of bioactive magnesium thioctic acid(MTA)layer formed by deposition and corrosion-resistant magnesium hydroxide(Mg(OH)_(2))layer grown in situ,is simply fabricated on ZE21B alloys via one-step electrodeposition.Scanning electron microscopy(SEM)shows that the electrodeposited coating has a compact and uniform structure.And the high adhesion of the MTA/Mg(OH)_(2)hybrid coating is also confirmed by the micro-scratch test.Electrochemical test,scanning kelvin probe(SKP),and hydrogen evolution measurement indicate that the hybrid coating effectively reduces the degradation rate of Mg substrates.Haemocompatibility experiment and cell culture trial detect that the composite coating is of fine biocompatibility.Finally,the preparation mechanism of MTA/Mg(OH)_(2)hybrid coatings is discussed and proposed.This coating shows a great potential application for cardiovascular stents.展开更多
This review paper explores the efficacy of magnesium ferrite-based catalysts in photocatalytic degradation of organic contaminates(antibiotic and dyes).We report the influence of different doping strategies,synthesis ...This review paper explores the efficacy of magnesium ferrite-based catalysts in photocatalytic degradation of organic contaminates(antibiotic and dyes).We report the influence of different doping strategies,synthesis methods,and composite materials on the degradation efficiency of these pollutants.Our analysis reveals the versatile and promising nature of magnesium ferrite-based catalysts,offering the valuable insights into their practical application for restoring the environment.Due to the smaller band gap and magnetic nature of magnesium ferrite,it holds the benefit of utilising the broader spectrum of light while also being recoverable.The in-depth analysis of magnesium ferrites'photocatalytic mechanism could lead to the development of cheap and reliable photocatalyst for the wastewater treatment.This concise review offers a thorough summary of the key advancements in this field,highlighting the pivotal role of the magnesium ferrite based photocatalysts in addressing the pressing global issue of organic pollutants in wastewater.展开更多
Among the existing series of softer metals,magnesium(Mg)has attracted much attention due to its impressive strength-to-weight ratio.However,due to its ease of deformability,Mg tends to suffer from rapid degradation in...Among the existing series of softer metals,magnesium(Mg)has attracted much attention due to its impressive strength-to-weight ratio.However,due to its ease of deformability,Mg tends to suffer from rapid degradation in a wide variety of abrasive and electrochemical environments.One method of improving its surface properties is through surface modification techniques.Among the existing techniques,laser shock peening(LSP)has been one of the most widely utilized processes due to its surface-hardening-like effects.Despite this understanding,a comprehensive review has yet to exist that encapsulates the strengthening mechanism of LSP for Mg and its influence in degradation environments.This review aims to encapsulate the existing research around the LSP field for Mg.Specifically,an understanding of the surface-strengthening effects in relation to its mechanical,tribological,corrosion,and tribo-corrosion characteristics is elucidated.Additionally,the feasibility of LSP for Mg materials in critical industries is also discussed.Through this work,a novel understanding of LSP for Mg can be understood,which can provide a future direction for research in this field.展开更多
Historically,the rapid degradation and massive gas release from magnesium(Mg)implants resulted in severe emphysema and mechanical failure.With the advent of new alloys and surface treatment methods,optimized Mg implan...Historically,the rapid degradation and massive gas release from magnesium(Mg)implants resulted in severe emphysema and mechanical failure.With the advent of new alloys and surface treatment methods,optimized Mg implants have re-entered clinics since last decade with reliable performance.However,the optimization aims at slowing down the degradation process,rather than exemption of the gas release.This study involved a systematic evaluation of current preclinical and clinical evidence,regarding the physical signs,symptoms,radiological features,pathological findings and complications potentially associated with peri±implant gas accumulation(PIGA)after musculoskeletal Mg implantation.The literature search identified 196 potentially relevant publications,and 51 papers were enrolled for further analysis,including 22 preclinical tests and 29 clinical studies published from 2005 to 2023.Various Mg-based materials have been evaluated in animal research,and the application of pure Mg and Mg alloys have been reported in clinical follow-ups involving multiple anatomical sites and musculoskeletal disorders.Soft tissue and intraosseous PIGA are common in both animal tests and clinical follow-ups,and potentially associated with certain adverse events.Radiological examinations especially micro-CT and clinical CT scans provide valuable information for quantitative and longitudinal analysis.While according to simulation tests involving Mg implantation and chemical processing,tissue fixation could lead to an increase in the volume of gas cavity,thus the results obtained from ex vivo imaging or histopathological evaluations should be interpreted with caution.There still lacks standardized procedures or consensus for both preclinical and clinical evaluation of PIGA.However,by providing focused insights into the topic,this evidence-based study will facilitate future animal tests and clinical evaluations,and support developing biocompatible Mg implants for the treatment of musculoskeletal disorders.展开更多
Biodegradable magnesium(Mg)and its alloys exhibit excellent biocompatibility and mechanical compatibility,demonstrating tremendous potential for applications in orthopedics.However,the rapid degradation rate has limit...Biodegradable magnesium(Mg)and its alloys exhibit excellent biocompatibility and mechanical compatibility,demonstrating tremendous potential for applications in orthopedics.However,the rapid degradation rate has limited their clinical application.Polycaprolactone(PCL)is commonly employed as a polymer coating to impede the rapid degradation of Mg.Unfortunately,its long-term anti-corrosion capability and bioactivity are inadequate.To address these issues,polydopamine(PDA)-modified zeolitic imidazolate framework-8(PZIF-8)bioactive nanoparticles are fabricated and incorporated into the PCL coating.The PZIF-8 particles,featuring catechol motifs,can enhance the compactness of the PCL coating,reduce its defects,and possess biomineralization ability,thereby effectively improving its anti-corrosive and bioactive properties.Moreover,the active substances released from the degradation of the PZIF-8 particles such as Zn^(2+)and PDA are beneficial for osteogenesis.The corrosion tests indicate that the corrosion current density of PCL-treated sample decreases by more than one order of magnitude and the amount of H_(2)released decreases from 0.23±0.12 to 0.08±0.08 ml cm^(-2)after doping with the PZIF-8.Furthermore,the improved corrosion resistance and released PDA and Zn^(2+)from the coating can promote osteogenic differentiation by up-regulating the expression of alkaline phosphatase activity,related osteogenic genes,and proteins.In addition,in vivo implantation experiments in rabbit femur defects further offer strong evidence that the doping of PZIF-8 nanoparticles accelerates bone reconstruction of the PCL coating.In summary,this work implies a new strategy to fabricate a PCL-based coating on Mg-based implants by introducing the PZIF-8 particles for orthopedic applications.展开更多
This paper provided an effective method to further improve the mechanical properties of the AZ80+0.4%Ce magnesium alloy wheel spoke.The effect of high strength and ductility was obtained with a yield strength of 295.3...This paper provided an effective method to further improve the mechanical properties of the AZ80+0.4%Ce magnesium alloy wheel spoke.The effect of high strength and ductility was obtained with a yield strength of 295.36 MPa,an elongation of 10%,by the combination of pre-deformation(7%deformation)and two-stage aging treatment(120℃/9 h+175℃/24 h).The evolution of the microstructure and properties of the alloy was explored under the coupling conditions of different pre-deformation degrees and multi-stage aging.The results show that,pre-deformation introduced a large number of(1012)tensile twinning and dislocations,which greatly promoted the probability of continuous precipitates(CPs)appearing.On the contrary,the discontinuous precipitates(DPs)were limited by the vertical and horizontal twin structure.As a result,the pre-nucleation method of two-stage aging increased the proportion of CPs by 34%-38%.Owing to the DPs was effectively suppressed,the alloy's yield strength has been greatly improved.Besides,under multi-stage aging,the twin boundaries induce protruding nucleation to form static recrystallization by hindering the migration of dislocations,and the matrix swallows the twins,then the texture gradually tilts from the two poles to the basal plane.As an important supplement,the grain refinement and oblique texture promoted the improvement of the yield strength of the component.展开更多
Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machi...Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machinability,good biocompatibility,and biodegradability.The primary shortcoming of Mg-based implants is their low corrosion resistance in the physiological environment,which results in premature mechanical integrity loss before adequate healing and the production of excessive hydrogen gas,which is harmful to the body tissues and negatively affects the biocompatibility of the implant.Laser surface modification has recently received attention because it can improve the surface properties such as surface chemistry,roughness,topography,corrosion resistance,wear resistance,hydrophilicity,and thus cell response to the surface of the material.The composition and microstructures including textures and phases of laser-treated surfaces depend largely on the laser processing parameters(input laser power,laser scan velocity,frequency,pulse duration,pressure,gas circulation,working time,spot size,beam focal position,and laser track overlap)and the thermophysical properties of the substrate(solubility,melting point,and boiling point).This review investigates the impacts of various laser surface modification techniques including laser surface melting,laser surface alloying,laser cladding,laser surface texturing,and laser shock peening,and highlights their significance in improving the surface properties of biodegradable Mg alloys for implant applications.Additionally,we explore how different laser process parameters affect its composition,microstructure,and surface properties in each laser surface modification technique.展开更多
文摘Realising the potential of Magnesium(Mg),several globally leading ventures have invested in the Mg industry,but their relatively poor corrosion resistance is a never ending saga till date.The corrosion and bio-corrosion behaviour of Mg has gained research attention and still remains a hot topic in the application of automobile,aerospace and biomedical industries.The intrinsic high electrochemical nature of Mg limits their utilization in diverse application.This scenario has prompted the development of Mg composites with an aim to achieve superior corrosion and bio-corrosion resistance.The present review enlightens the influence of grain size(GS),secondary phase,texture,type of matrix and reinforcement on the corrosion and bio-corrosion behaviour of Mg composites.Firstly,the corrosion and bio-corrosion behaviour of Mg composites manufactured by primary and secondary processing routes are elucidated.Secondly,the comprehensive corrosion and bio-corrosion mechanisms of these Mg composites are proposed.Thirdly,the individual role of GS,texture and corrosive medium on corrosion and bio-corrosion behaviour of Mg composites are clarified and revealed.The challenges encountered,unanswered issues in this field are explained in detail and accordingly the scope for future research is framed.The review is presented from basic concrete background to advanced corrosion mechanisms with an aim of creating interest among the readers like students,researchers and industry experts from various research backgrounds.Indeed,the corrosion and bio-corrosion behaviour of Mg composites are critically reviewed for the first time to:(i)contribute to the body of knowledge,(ii)foster research and development,(iii)make breakthrough,and(iv)create life changing innovations in the field of Mg composite corrosion.
基金funded by the National Key Research and Development Program of China(2018YFE0104200)National Natural Science Foundation of China(51875310,52175274,82172065)Tsinghua Precision Medicine Foundation.
文摘Laser powder bed fusion(L-PBF)of Mg alloys has provided tremendous opportunities for customized production of aeronautical and medical parts.Layer thickness(LT)is of great significance to the L-PBF process but has not been studied for Mg alloys.In this study,WE43 Mg alloy bulk cubes,porous scaffolds,and thin walls with layer thicknesses of 10,20,30,and 40μm were fabricated.The required laser energy input increased with increasing layer thickness and was different for the bulk cubes and porous scaffolds.Porosity tended to occur at the connection joints in porous scaffolds for LT40 and could be eliminated by reducing the laser energy input.For thin wall parts,a large overhang angle or a small wall thickness resulted in porosity when a large layer thicknesses was used,and the porosity disappeared by reducing the layer thickness or laser energy input.A deeper keyhole penetration was found in all occasions with porosity,explaining the influence of layer thickness,geometrical structure,and laser energy input on the porosity.All the samples achieved a high fusion quality with a relative density of over 99.5%using the optimized laser energy input.The increased layer thickness resulted to more precipitation phases,finer grain sizes and decreased grain texture.With the similar high fusion quality,the tensile strength and elongation of bulk samples were significantly improved from 257 MPa and 1.41%with the 10μm layer to 287 MPa and 15.12%with the 40μm layer,in accordance with the microstructural change.The effect of layer thickness on the compressive properties of porous scaffolds was limited.However,the corrosion rate of bulk samples accelerated with increasing the layer thickness,mainly attributed to the increased number of precipitation phases.
基金This work was financially supported by the National Key Research and Development Program of China(No.2021YFB3701100)the National Natural Science Foundation of China(Nos.52171104 and U20A20234)+1 种基金the Chongqing Research Program of Basic Research and Frontier Technology,China(Nos.cstc2021ycjh-bgzxm0086 and 2019jcyj-msxmX0306)the fundamental Research funds for Central Universities,China(Nos.SKLMT-ZZKT-2022R04,2021CDJJMRH-001,and SKLMT-ZZKT-2022M12).
文摘More than 4600 papers in the field of Mg and Mg alloys were published and indexed in the Web of Science(WoS)Core Collection database in 2022.The bibliometric analyses indicate that the microstructure,mechanical properties,and corrosion of Mg alloys are still the main research focus.Bio-Mg materials,Mg ion batteries and hydrogen storage Mg materials have attracted much attention.Notable contributions to the research and development of magnesium alloys were made by Chongqing University(>200 papers),Chinese Academy of Sciences,Shanghai Jiao Tong University,and Northeastern University(>100 papers)in China,Helmholtz Zentrum Hereon in Germany,Ohio State University in the USA,the University of Queensland in Australia,Kumanto University in Japan,and Seoul National University in Korea,University of Tehran in Iran,and National University of Singapore in Singapore,etc.This review is aimed to summarize the progress in the development of structural and functional Mg and Mg alloys in 2022.Based on the issues and challenges identified here,some future research directions are suggested.
基金supported by National Key Research and Development Program of China[2023YFB4605800]National Natural Science Foundation of China[51935014,52165043]+3 种基金JiangXi Provincial Natural Science Foundation of China[20224ACB204013,20224ACB214008]Jiangxi Provincial Cultivation Program for Academic and Technical Leaders of Major Subjects[20225BCJ23008]Anhui Provincial Natural Science Foundation[2308085ME171]The University Synergy Innovation Program of Anhui Province[GXXT-2023-025,GXXT-2023-026].
文摘Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical properties.The incorporation of rare earth(RE)elements,with their distinct physical and chemical properties,has greatly contributed to enhancing the mechanical performance,degradation behavior,and biological performance of biomedical Mg alloys.Currently,a series of RE-Mg alloys are being designed and investigated for orthopedic implants and cardiovascular stents,achieving substantial and encouraging research progress.In this work,a comprehensive summary of the state-of-the-art in biomedical RE-Mg alloys is provided.The physiological effects and design standards of RE elements in biomedical Mg alloys are discussed.Particularly,the degradation behavior and mechanical properties,including their underlying action are studied in-depth.Furthermore,the preparation techniques and current application status of RE-Mg alloys are reviewed.Finally,we address the ongoing challenges and propose future prospects to guide the development of high-performance biomedical Mg-RE alloys.
基金supported by the National Natural Science Foundation of China(Grant Nos.12272001,11972046)the Outstanding Youth Project of Natural Science Foundation of Anhui Province(Grant No.2108085Y02)the Major Project of Anhui University Natural Science Foundation(Grant No.KJ2020ZD30)。
文摘The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the two-color pyrometer technique,and the chemical composition of solid combustion residues were analyzed.The experimental results showed that the average flame propagation velocities of 23μm,40μm,60μm and 103μm MgH_(2)dust clouds in the stable propagation stage were 3.7 m/s,2.8 m/s,2.1 m/s and 0.9 m/s,respectively.The dust clouds with smaller particle sizes had faster flame propagation velocity and stronger oscillation intensity,and their flame temperature distributions were more even and the temperature gradients were smaller.The flame structures of MgH_(2)dust clouds were significantly affected by the particle sinking velocity,and the combustion processes were accompanied by micro-explosion of particles.The falling velocities of 23μm and 40μm MgH_(2)particles were 2.24 cm/s and 6.71 cm/s,respectively.While the falling velocities of 60μm and 103μm MgH_(2)particles were as high as 15.07 cm/s and 44.42 cm/s,respectively,leading to a more rapid downward development and irregular shape of the flame.Furthermore,the dehydrogenation reaction had a significant effect on the combustion performance of MgH_(2)dust.The combustion of H_(2)enhanced the ignition and combustion characteristics of MgH_(2)dust,resulting in a much higher explosion power than the pure Mg dust.The micro-structure characteristics and combustion residues composition analysis of MgH_(2)dust indicated that the combustion control mechanism of MgH_(2)dust flame was mainly the heterogeneous reaction,which was affected by the dehydrogenation reaction.
基金supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region(152131/18E).
文摘This study offers significant insights into the multi-physics phenomena of the SLM process and the subsequent porosity characteristics of ZK60 Magnesium(Mg)alloys.High-speed in-situ monitoring was employed to visualise process signals in real-time,elucidating the dynamics of melt pools and vapour plumes under varying laser power conditions specifically between 40 W and 60 W.Detailed morphological analysis was performed using Scanning-Electron Microscopy(SEM),demonstrating a critical correlation between laser power and pore formation.Lower laser power led to increased pore coverage,whereas a denser structure was observed at higher laser power.This laser power influence on porosity was further confirmed via Optical Microscopy(OM)conducted on both top and cross-sectional surfaces of the samples.An increase in laser power resulted in a decrease in pore coverage and pore size,potentially leading to a denser printed part of Mg alloy.X-ray Computed Tomography(XCT)augmented these findings by providing a 3D volumetric representation of the sample internal structure,revealing an inverse relationship between laser power and overall pore volume.Lower laser power appeared to favour the formation of interconnected pores,while a reduction in interconnected pores and an increase in isolated pores were observed at higher power.The interplay between melt pool size,vapour plume effects,and laser power was found to significantly influence the resulting porosity,indicating a need for effective management of these factors to optimise the SLM process of Mg alloys.
基金supported by National Key Research and Development Program of China(2021YFB4000604)National Natural Science Foundation of China(52271220)111 Project(B12015)and the Fundamental Research Funds for the Central Universities.
文摘Hydrogen energy has emerged as a pivotal solution to address the global energy crisis and pave the way for a cleaner,low-carbon,secure,and efficient modern energy system.A key imperative in the utilization of hydrogen energy lies in the development of high-performance hydrogen storage materials.Magnesium-based hydrogen storage materials exhibit remarkable advantages,including high hydrogen storage density,cost-effectiveness,and abundant magnesium resources,making them highly promising for the hydrogen energy sector.Nonetheless,practical applications of magnesium hydride for hydrogen storage face significant challenges,primarily due to their slow kinetics and stable thermodynamic properties.Herein,we briefly summarize the thermodynamic and kinetic properties of MgH2,encompassing strategies such as alloying,nanoscaling,catalyst doping,and composite system construction to enhance its hydrogen storage performance.Notably,nanoscaling and catalyst doping have emerged as more effective modification strategies.The discussion focuses on the thermodynamic changes induced by nanoscaling and the kinetic enhancements resulting from catalyst doping.Particular emphasis lies in the synergistic improvement strategy of incorporating nanocatalysts with confinement materials,and we revisit typical works on the multi-strategy optimization of MgH2.In conclusion,we conduct an analysis of outstanding challenges and issues,followed by presenting future research and development prospects for MgH2 as hydrogen storage materials.
基金financially supported by the National Key Research and Development Program of China(Nos.2022 YFB3709300 and 2021YFB3701000)the National Natural Science Foundation of China(Nos.52271090 and 52071036)+1 种基金the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030006)the Independent Research Project of State Key Laboratory of Mechanical Transmissions(Nos.SKLMT-ZZKT-2022Z01 and S KLMT-ZZKT-2022M12)。
文摘Magnesium and magnesium alloy foils have great potential for application in battery anodes,electromagnetic shielding,optics and acoustics,and biology because of their excellent specific damping,internal dissipation coefficients,magnetic and electrical conductivities,as well as high theoretical specific capacity.However,magnesium alloys exhibit poor deformation ability due to their hexagonal close-packed crystal structure.Preparing magnesium and magnesium alloy foils with thicknesses of less than 0.1 mm is difficult because of surface oxidation and grain growth at high temperatures or severe anisotropy after cold rolling that leads to cracks.Numerous methods have been applied to prepare magnesium alloy foils.They include warm rolling,cold rolling,accumulative roll bonding,electric plastic rolling,and on-line heating rolling.Defects of magnesium and magnesium alloy foils during preparation,such as edge cracks and breakage,are important factors for consideration.Herein,the current status of the research on magnesium and magnesium alloy foils is summarized from the aspects of foil preparation,defect control,performance characterization,and application prospects.The advantages and disadvantages of different preparation methods and defect(edge cracks and breakage)mechanisms in the preparation of foils are identified.
文摘Nonunion represents a crucial challenge in orthopedic medicine,demanding innovative solutions beyond the scope of traditional bone grafting methods.Among the various strategies available,magnesium(Mg)implants have been recognized for their biocompatibility and biodegradability.However,their susceptibility to rapid corrosion and degradation has garnered notable research interest in bone tissue engineering(BTE),particularly in the development of Mg-incorporated biocomposite scaffolds.These scaffolds gradually release Mg2+,which enhances immunomodulation,osteogenesis,and angiogenesis,thus facilitating effective bone regeneration.This review presents myriad fabrication techniques used to create Mg-incorporated biocomposite scaffolds,including electrospinning,three-dimensional printing,and sol-gel synthesis.Despite these advancements,the application of Mg-incorporated biocomposite scaffolds faces challenges such as controlling the degradation rate of Mg and ensuring mechanical stability.These limitations highlight the necessity for ongoing research aimed at refining fabrication techniques to better regulate the physicochemical and osteogenic properties of scaffolds.This review provides insights into the potential of Mg-incorporated biocomposite scaffolds for BTE and the challenges that need to be addressed for their successful translation into clinical applications.
基金Funded by the Shandong Provincial Natural Science Foundation(No.ZR2022MB060)the Project of Shandong Province Higher Educational Young Innovative Talent Introduction and Cultivation Team(Hydrogen Energy Chemistry Innovation Team)。
文摘The lignite-derived carbon from self-protection pyrolysis was employed to balance the fracturing and cold-welding of magnesium during ball milling.Particle size analysis indicates that the introduction of lignite-derived carbon can effectively reduce the particle size of Mg while the introduction of graphite does no help.Besides,the effect of lignite-derived carbon on crystallite size reduction of Mg is also better than graphite.A moderate cold-welding phenomenon was observed after ball-milling Mg with the lignite-derived carbon,suggesting less Mg is wasted on the milling vials and balls.Molecular dynamic simulations reveal that the balanced fracturing and cold-welding of magnesium during ball milling is mainly attributed to the special structure of the lignite-derived carbon:graphitized short-range ordered stacking function as dry lubricant and irregular shape/sharp edge function as milling aid.The preliminary findings in current study are expected to offer implications for designing efficient Mg-based hydrogen storage materials.
基金supported by National Natural Science Foundation of China(52371095)Innovation Research Group of Universities in Chongqing(CXQT21030)+2 种基金Chongqing Talents:Exceptional Young Talents Project(CQYC201905100)Chongqing Youth Expert Studio,Chongqing Overseas Chinese Entrepreneurship and Innovation Support Program(cx2023117)Chongqing Natural Science Foundation Innovation and Development Joint Fund(CSTB 2022NS CQLZX0054)。
文摘Metal-air battery is an environmental friendly energy storage system with unique open structure.Magnesium(Mg)and its alloys have been extensively attempted as anodes for air batteries due to high theoretical energy density,low cost,and recyclability.However,the study on Mg-air battery(MAB)is still at the laboratory level currently,mainly owing to the low anodic efficiency caused by the poor corrosion resistance.In order to reduce corrosion losses and achieve optimal utilization efficiency of Mg anode,the design strategies are reviewed from microstructure perspectives.Firstly,the corrosion behaviors have been discussed,especially the negative difference effect derived by hydrogen evolution.Special attention is given to the effect of anode micro-structures on the MAB,which includes grain size,grain orientation,second phases,crystal structure,twins,and dislocations.For further improvement,the discharge performance,long period stacking ordered phase and its enhancing effect are considered.Meanwhile,given the current debates over Mg dendrites,the potential risk,the impact on discharge,and the elimination strategies are discussed.Microstructure control and single crystal would be promising ways for MAB anode.
基金supported by the Office of Scientific Research of Shandong Vocational and Technical University of International Studies.
文摘This review focuses on thermodynamic and physical parameters,synthesis methods,and reported phases of Magnesium(Mg)containing high-entropy alloys(HEAs).Statistical data of publications concerning Mg-containing HEAs were collected and analyzed.Data on the chemical elements included in Mg-containing HEAs,their theoretical end experimental densities,thermodynamic parameters,physical parameters,fabricated techniques and reported phases were also collected and discussed.On the basis of this information,a new classification for HEAs was proposed.It is also shown that the existing thermodynamic parameters cannot accurately predict the formation of a single phase solid solution for Mg-containing HEAs.The physical parameters of Mg-containing HEAs are within a wide range,and most of the synthesized Mg-containing HEAs have a complex multiphase structure.
文摘Electric arc furnace(EAF)dust is an important secondary resource containing metals,such as zinc(Zn)and iron(Fe).Recover-ing Zn from EAF dust can contribute to resource recycling and reduce environmental impacts.However,the high chemical stability of ZnFe_(2)O_(4)in EAF dust poses challenges to Zn recovery.To address this issue,a facile approach that involves oxygen-assisted chlorination using molten MgCl_(2)is proposed.This work focused on elucidating the role of O2 in the reaction between ZnFe_(2)O_(4)and molten MgCl_(2).The results demonstrate that MgCl_(2)effectively broke down the ZnFe_(2)O_(4)structure,and the high O2 atmosphere considerably promoted the sep-aration of Zn from other components in the form of ZnCl_(2).The presence of O2 facilitated the formation of MgFe_(2)O_(4),which stabilized Fe and prevented its chlorination.Furthermore,the excessive use of MgCl_(2)resulted in increased evaporation loss,and high temperatures pro-moted the rapid separation of Zn.Building on these findings,we successfully extracted ZnCl_(2)-enriched volatiles from practical EAF dust through oxygen-assisted chlorination.Under optimized conditions,this method achieved exceptional Zn chlorination percentage of over 97%within a short period,while Fe chlorination remained below 1%.The resulting volatiles contained 85wt%of ZnCl_(2),which can be further processed to produce metallic Zn.The findings offer guidance for the selective recovery of valuable metals,particularly from solid wastes such as EAF dust.
基金the National Key Research and Development Program of China(2018YFC1106703)the National Natural Science Foundation of China(No.U1804251)。
文摘Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based stents.Nevertheless,the steps for preparing composite coatings are usually complicated and time-consuming.Herein,a novel composite coating,composed of bioactive magnesium thioctic acid(MTA)layer formed by deposition and corrosion-resistant magnesium hydroxide(Mg(OH)_(2))layer grown in situ,is simply fabricated on ZE21B alloys via one-step electrodeposition.Scanning electron microscopy(SEM)shows that the electrodeposited coating has a compact and uniform structure.And the high adhesion of the MTA/Mg(OH)_(2)hybrid coating is also confirmed by the micro-scratch test.Electrochemical test,scanning kelvin probe(SKP),and hydrogen evolution measurement indicate that the hybrid coating effectively reduces the degradation rate of Mg substrates.Haemocompatibility experiment and cell culture trial detect that the composite coating is of fine biocompatibility.Finally,the preparation mechanism of MTA/Mg(OH)_(2)hybrid coatings is discussed and proposed.This coating shows a great potential application for cardiovascular stents.
文摘This review paper explores the efficacy of magnesium ferrite-based catalysts in photocatalytic degradation of organic contaminates(antibiotic and dyes).We report the influence of different doping strategies,synthesis methods,and composite materials on the degradation efficiency of these pollutants.Our analysis reveals the versatile and promising nature of magnesium ferrite-based catalysts,offering the valuable insights into their practical application for restoring the environment.Due to the smaller band gap and magnetic nature of magnesium ferrite,it holds the benefit of utilising the broader spectrum of light while also being recoverable.The in-depth analysis of magnesium ferrites'photocatalytic mechanism could lead to the development of cheap and reliable photocatalyst for the wastewater treatment.This concise review offers a thorough summary of the key advancements in this field,highlighting the pivotal role of the magnesium ferrite based photocatalysts in addressing the pressing global issue of organic pollutants in wastewater.
文摘Among the existing series of softer metals,magnesium(Mg)has attracted much attention due to its impressive strength-to-weight ratio.However,due to its ease of deformability,Mg tends to suffer from rapid degradation in a wide variety of abrasive and electrochemical environments.One method of improving its surface properties is through surface modification techniques.Among the existing techniques,laser shock peening(LSP)has been one of the most widely utilized processes due to its surface-hardening-like effects.Despite this understanding,a comprehensive review has yet to exist that encapsulates the strengthening mechanism of LSP for Mg and its influence in degradation environments.This review aims to encapsulate the existing research around the LSP field for Mg.Specifically,an understanding of the surface-strengthening effects in relation to its mechanical,tribological,corrosion,and tribo-corrosion characteristics is elucidated.Additionally,the feasibility of LSP for Mg materials in critical industries is also discussed.Through this work,a novel understanding of LSP for Mg can be understood,which can provide a future direction for research in this field.
基金a grant from the state of Schleswig-Holstein and the European Union ERDF-European Regional Development Fund(Zukunftsprogramm Wirtschaft)。
文摘Historically,the rapid degradation and massive gas release from magnesium(Mg)implants resulted in severe emphysema and mechanical failure.With the advent of new alloys and surface treatment methods,optimized Mg implants have re-entered clinics since last decade with reliable performance.However,the optimization aims at slowing down the degradation process,rather than exemption of the gas release.This study involved a systematic evaluation of current preclinical and clinical evidence,regarding the physical signs,symptoms,radiological features,pathological findings and complications potentially associated with peri±implant gas accumulation(PIGA)after musculoskeletal Mg implantation.The literature search identified 196 potentially relevant publications,and 51 papers were enrolled for further analysis,including 22 preclinical tests and 29 clinical studies published from 2005 to 2023.Various Mg-based materials have been evaluated in animal research,and the application of pure Mg and Mg alloys have been reported in clinical follow-ups involving multiple anatomical sites and musculoskeletal disorders.Soft tissue and intraosseous PIGA are common in both animal tests and clinical follow-ups,and potentially associated with certain adverse events.Radiological examinations especially micro-CT and clinical CT scans provide valuable information for quantitative and longitudinal analysis.While according to simulation tests involving Mg implantation and chemical processing,tissue fixation could lead to an increase in the volume of gas cavity,thus the results obtained from ex vivo imaging or histopathological evaluations should be interpreted with caution.There still lacks standardized procedures or consensus for both preclinical and clinical evaluation of PIGA.However,by providing focused insights into the topic,this evidence-based study will facilitate future animal tests and clinical evaluations,and support developing biocompatible Mg implants for the treatment of musculoskeletal disorders.
基金financially supported by the Guangzhou Science and Technology Project(Nos.2021A0505030042 and 201904010060)Guangdong Basic and Applied Basic Research Foundation(No.2020B1515120078)+2 种基金National Natural Science Foundation of China(Nos.81401766 and 32101059)Natural Science Foundation of Guangdong Province(No.2022A1515010266)Shenzhen Key Laboratory of Musculoskeletal Tissue Reconstruction and Function Restoration and Shenzhen People’s Hospital(No.ZDSYS20200811143752005)。
文摘Biodegradable magnesium(Mg)and its alloys exhibit excellent biocompatibility and mechanical compatibility,demonstrating tremendous potential for applications in orthopedics.However,the rapid degradation rate has limited their clinical application.Polycaprolactone(PCL)is commonly employed as a polymer coating to impede the rapid degradation of Mg.Unfortunately,its long-term anti-corrosion capability and bioactivity are inadequate.To address these issues,polydopamine(PDA)-modified zeolitic imidazolate framework-8(PZIF-8)bioactive nanoparticles are fabricated and incorporated into the PCL coating.The PZIF-8 particles,featuring catechol motifs,can enhance the compactness of the PCL coating,reduce its defects,and possess biomineralization ability,thereby effectively improving its anti-corrosive and bioactive properties.Moreover,the active substances released from the degradation of the PZIF-8 particles such as Zn^(2+)and PDA are beneficial for osteogenesis.The corrosion tests indicate that the corrosion current density of PCL-treated sample decreases by more than one order of magnitude and the amount of H_(2)released decreases from 0.23±0.12 to 0.08±0.08 ml cm^(-2)after doping with the PZIF-8.Furthermore,the improved corrosion resistance and released PDA and Zn^(2+)from the coating can promote osteogenic differentiation by up-regulating the expression of alkaline phosphatase activity,related osteogenic genes,and proteins.In addition,in vivo implantation experiments in rabbit femur defects further offer strong evidence that the doping of PZIF-8 nanoparticles accelerates bone reconstruction of the PCL coating.In summary,this work implies a new strategy to fabricate a PCL-based coating on Mg-based implants by introducing the PZIF-8 particles for orthopedic applications.
基金the financial supports from Program for the Supported by the Innovative Talents Support Program of Higher Education Institutions in Shanxi Provincethe‘Shanxi Province’s Key Core Technology and Common Technology Research And Development Special Project’(2020XXX015)Special Project for Scientific and Technological Cooperation and Exchange in Shanxi Province(regional cooperation project):Key Technologies for flexible manufacturing of high-strength heat-resistant magnesium alloy cabin components(202104041101033)。
文摘This paper provided an effective method to further improve the mechanical properties of the AZ80+0.4%Ce magnesium alloy wheel spoke.The effect of high strength and ductility was obtained with a yield strength of 295.36 MPa,an elongation of 10%,by the combination of pre-deformation(7%deformation)and two-stage aging treatment(120℃/9 h+175℃/24 h).The evolution of the microstructure and properties of the alloy was explored under the coupling conditions of different pre-deformation degrees and multi-stage aging.The results show that,pre-deformation introduced a large number of(1012)tensile twinning and dislocations,which greatly promoted the probability of continuous precipitates(CPs)appearing.On the contrary,the discontinuous precipitates(DPs)were limited by the vertical and horizontal twin structure.As a result,the pre-nucleation method of two-stage aging increased the proportion of CPs by 34%-38%.Owing to the DPs was effectively suppressed,the alloy's yield strength has been greatly improved.Besides,under multi-stage aging,the twin boundaries induce protruding nucleation to form static recrystallization by hindering the migration of dislocations,and the matrix swallows the twins,then the texture gradually tilts from the two poles to the basal plane.As an important supplement,the grain refinement and oblique texture promoted the improvement of the yield strength of the component.
基金the Australian Research Council(ARC)through the discovery grant DP210101862。
文摘Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machinability,good biocompatibility,and biodegradability.The primary shortcoming of Mg-based implants is their low corrosion resistance in the physiological environment,which results in premature mechanical integrity loss before adequate healing and the production of excessive hydrogen gas,which is harmful to the body tissues and negatively affects the biocompatibility of the implant.Laser surface modification has recently received attention because it can improve the surface properties such as surface chemistry,roughness,topography,corrosion resistance,wear resistance,hydrophilicity,and thus cell response to the surface of the material.The composition and microstructures including textures and phases of laser-treated surfaces depend largely on the laser processing parameters(input laser power,laser scan velocity,frequency,pulse duration,pressure,gas circulation,working time,spot size,beam focal position,and laser track overlap)and the thermophysical properties of the substrate(solubility,melting point,and boiling point).This review investigates the impacts of various laser surface modification techniques including laser surface melting,laser surface alloying,laser cladding,laser surface texturing,and laser shock peening,and highlights their significance in improving the surface properties of biodegradable Mg alloys for implant applications.Additionally,we explore how different laser process parameters affect its composition,microstructure,and surface properties in each laser surface modification technique.