Within the past ten years,spark plasma sintering(SPS)has become an increasingly popular process for Mg manufacturing.In the SPS process,interparticle diffusion of compressed particles is rapidly achieved due to the co...Within the past ten years,spark plasma sintering(SPS)has become an increasingly popular process for Mg manufacturing.In the SPS process,interparticle diffusion of compressed particles is rapidly achieved due to the concept of Joule heating.Compared to traditional and additive manufacturing(AM)techniques,SPS gives unique control of the structural and microstructural features of Mg components.By doing so,their mechanical,tribological,and corrosion properties can be tailored.Although great advancements in this field have been made,these pieces of knowledge are scattered and have not been contextualized into a single work.The motivation of this work is to address this scientific gap and to provide a groundwork for understanding the basics of SPS manufacturing for Mg.To do so,the existing body of SPS Mg literature was first surveyed,with a focus on their structural formation and degradation mechanisms.It was found that successful Mg SPS fabrication highly depended on the processing temperature,particle size,and particle crystallinity.The addition of metal and ceramic composites also affected their microstructural features due to the Zener pinning effect.In degradative environments,their performance depends on their structural features and whether they have secondary phased composites.In industrial applications,SPS'd Mg was found to have great potential in biomedical,hydrogen storage,battery,automotive,and recycling sectors.The prospects to advance the field include using Mg as a doping agent for crystallite size refinement and using bulk metallic Mg-based glass powders for amorphous SPS components.Despite these findings,the interactions of multi-composites on the processing-structure-property relationships of SPS Mg is not well understood.In total,this work will provide a useful direction in the SPS field and serve as a milestone for future Mg-based SPS manufacturing.展开更多
Anodic films were successfully fabricated on Ti6A14V alloy by anodic oxidation method in an environmental friendly electrolyte with and without sodium hypochlorite. The anodic films were characterized by means of the ...Anodic films were successfully fabricated on Ti6A14V alloy by anodic oxidation method in an environmental friendly electrolyte with and without sodium hypochlorite. The anodic films were characterized by means of the scanning electron microscope （SEM） and energy dispersive spectrometer （EDS）. Results revealed that the addition of sodium hypochlorite leads to the ultrafast growth of oxide films, and results in the significant changes of morphology and thickness. The influence of sodium hypochlorite on formation and crystallization of oxide films as a function of anodizing time was discussed. Meanwhile, potentiodynamic electrochemical tests and dry sliding wear tests were performed to evaluate the corrosion resistance and tribological properties of oxide films. It was found that the oxide film fabricated with the existence of sodium hypochlorite had improved corrosion resistance and tribological properties than the one formed without sodium hypochlorite. Moreover, the effect mechanism of sodium hypochlorite on the growth rate and surface morphologies of oxide films during the anodizing process was discussed. It was found that hypochlorite ions participated in the reaction on anode which causes the rapid growth of oxide films and then affect the whole anodizing process.展开更多
The main mechanism of rare-earth element Sc on the microstructure and properties of Zr-8.8Si biomaterial alloy was explored.The novel Zr-8.8Si-xSc(x=0,5,10 and 15 at.%)alloys were prepared by electric arc smelting wit...The main mechanism of rare-earth element Sc on the microstructure and properties of Zr-8.8Si biomaterial alloy was explored.The novel Zr-8.8Si-xSc(x=0,5,10 and 15 at.%)alloys were prepared by electric arc smelting with Ar protection.The microstructural and mechanical properties as well as electrochemical corrosion and tribological behaviors in artificial saliva solution of the Zr-8.8Si-xSc alloys were systematically studied.The results show that the Zr-8.8Si-xSc alloys only consist of two-phase α-Zr and Zr_(3)Si,Sc dissolve in α-Zr matrix to form Zr-Sc solid solution.The addition of Sc is conducive to refine microstructure,and reduce micro-pores of Zr-8.8Si alloy which lead to higher Young's modulus,compressive strength and micro-hardness.Among them,the highest value of Young's modulus is 31.5 GPa,still at a low level in biomedical alloy.The promotion of corrosion resistance can be attributed to the addition of Sc which can accelerate the formation of passive film,slow down the appearance of pitting and reduce the accumulation of corrosion products in surface.Under the condition of sliding wear test with artificial saliva solution,compared with Zr-8.8Si-0Sc alloy,the wear loss of samples with Sc is greatly decreased,and wear resistance is increased with increasing content of Sc.The experimental results indicate that the combination of good mechanical properties,corrosion resistance and tribological properties of Zr-8.8Si-(5,10 and 15 at.%)Sc alloys was much better than Zr-8.8Si-0Sc alloy.Among them,the comprehensive property of Zr-8.8Si-10Sc alloy is preferable in this work.展开更多
In recent years,high-entropy alloys(HEAs)have become a research hotspot in materials community,and great progress has been made in exploring various high-performance HEAs.As a special class,the light-weight refractory...In recent years,high-entropy alloys(HEAs)have become a research hotspot in materials community,and great progress has been made in exploring various high-performance HEAs.As a special class,the light-weight refractory high-entropy alloys(RHEAs)own both excellent high-temperature comprehensive properties and low density and have accordingly attracted more and more attention.In this paper,we presented a comprehensive review of the recent progress and status in light-weight RHEAs.Based on an exhausting search of the literature reports,one strategy in terms of phase numbers after preparation was first proposed to classify the light-weight RHEAs into three categories.Then,the status on the fundamental thermodynamic and thermophysical data/databases,computational approaches for alloy designing,and preparation/fabrication techniques of light-weight RHEAs was introduced one after another.After that,the progress on mechanical properties and oxidation/corrosion/wear behaviors of light-weight RHEAs at room and high temperatures was summarized.Finally,the conclusions of this review were drawn.By pointing out the shortcomings of the current research,the follow-up development directions in the field of light-weight RHEAs were also given.展开更多
Anodic oxidation is a prevalent technique to introduce superior corrosion and wear resistance upon the surface of titanium(Ti)alloys,in which the selection of appropriate electrolytes and defect-sealing strategies is ...Anodic oxidation is a prevalent technique to introduce superior corrosion and wear resistance upon the surface of titanium(Ti)alloys,in which the selection of appropriate electrolytes and defect-sealing strategies is a key.This study aims to address such issues through anodizing Ti-10V-2Fe-3Al alloy in malic acid,followed by a post-sealing treatment with Mg-Al layered double hydroxides(LDHs).The characteristics of the samples were investigated using scanning electron microscopy(SEM),atomic force microscopy(AFM),glow discharge optical emission spectroscopy(GDOES),X-ray diffraction(XRD)and energy-dispersive X-ray spectroscopy(EDS).SEM micrographs reveals that the anodic coating had a surface full of bulges and cracks,and was almost sealed by the following LDHs treatment.XRD pattern indicate that the anodic coating was mainly consisted of amorphous TiO2 with a small fraction of anatase,but its crystallization degree was increased through the post-sealing.Moreover,electrochemical and tribological measurements demonstrate that corrosion current density was 2.8×10-6,2.0×10-7,5.9×10-9A cm-2,and wear rate was 1.45×10-3,1.30×10-4 and 6.90×10-5 mm3 N-1 m-1 for respective bare Ti-10V-2Fe-3Al alloy substrate,anodized specimens without and with the LDHs post treatment.Finally,a plausible wear mechanism was proposed.展开更多
文摘Within the past ten years,spark plasma sintering(SPS)has become an increasingly popular process for Mg manufacturing.In the SPS process,interparticle diffusion of compressed particles is rapidly achieved due to the concept of Joule heating.Compared to traditional and additive manufacturing(AM)techniques,SPS gives unique control of the structural and microstructural features of Mg components.By doing so,their mechanical,tribological,and corrosion properties can be tailored.Although great advancements in this field have been made,these pieces of knowledge are scattered and have not been contextualized into a single work.The motivation of this work is to address this scientific gap and to provide a groundwork for understanding the basics of SPS manufacturing for Mg.To do so,the existing body of SPS Mg literature was first surveyed,with a focus on their structural formation and degradation mechanisms.It was found that successful Mg SPS fabrication highly depended on the processing temperature,particle size,and particle crystallinity.The addition of metal and ceramic composites also affected their microstructural features due to the Zener pinning effect.In degradative environments,their performance depends on their structural features and whether they have secondary phased composites.In industrial applications,SPS'd Mg was found to have great potential in biomedical,hydrogen storage,battery,automotive,and recycling sectors.The prospects to advance the field include using Mg as a doping agent for crystallite size refinement and using bulk metallic Mg-based glass powders for amorphous SPS components.Despite these findings,the interactions of multi-composites on the processing-structure-property relationships of SPS Mg is not well understood.In total,this work will provide a useful direction in the SPS field and serve as a milestone for future Mg-based SPS manufacturing.
基金Project(51271012)supported by the National Natural Science Foundation of China
文摘Anodic films were successfully fabricated on Ti6A14V alloy by anodic oxidation method in an environmental friendly electrolyte with and without sodium hypochlorite. The anodic films were characterized by means of the scanning electron microscope （SEM） and energy dispersive spectrometer （EDS）. Results revealed that the addition of sodium hypochlorite leads to the ultrafast growth of oxide films, and results in the significant changes of morphology and thickness. The influence of sodium hypochlorite on formation and crystallization of oxide films as a function of anodizing time was discussed. Meanwhile, potentiodynamic electrochemical tests and dry sliding wear tests were performed to evaluate the corrosion resistance and tribological properties of oxide films. It was found that the oxide film fabricated with the existence of sodium hypochlorite had improved corrosion resistance and tribological properties than the one formed without sodium hypochlorite. Moreover, the effect mechanism of sodium hypochlorite on the growth rate and surface morphologies of oxide films during the anodizing process was discussed. It was found that hypochlorite ions participated in the reaction on anode which causes the rapid growth of oxide films and then affect the whole anodizing process.
基金jointly supported by the Guangxi Natural Science Foundation(2018JJD160006,2019JJA 160077)the National Natural Science Foundation of China(51761002)+2 种基金the National Key R&D Program of China(2016YFB0301400)the Training Plan of High-Level Talents of Guangxi University(2015)the research project of Guangxi Key Laboratory of Processing for Non-ferrous Metallic and Featured Materials(GXYSSF1807).
文摘The main mechanism of rare-earth element Sc on the microstructure and properties of Zr-8.8Si biomaterial alloy was explored.The novel Zr-8.8Si-xSc(x=0,5,10 and 15 at.%)alloys were prepared by electric arc smelting with Ar protection.The microstructural and mechanical properties as well as electrochemical corrosion and tribological behaviors in artificial saliva solution of the Zr-8.8Si-xSc alloys were systematically studied.The results show that the Zr-8.8Si-xSc alloys only consist of two-phase α-Zr and Zr_(3)Si,Sc dissolve in α-Zr matrix to form Zr-Sc solid solution.The addition of Sc is conducive to refine microstructure,and reduce micro-pores of Zr-8.8Si alloy which lead to higher Young's modulus,compressive strength and micro-hardness.Among them,the highest value of Young's modulus is 31.5 GPa,still at a low level in biomedical alloy.The promotion of corrosion resistance can be attributed to the addition of Sc which can accelerate the formation of passive film,slow down the appearance of pitting and reduce the accumulation of corrosion products in surface.Under the condition of sliding wear test with artificial saliva solution,compared with Zr-8.8Si-0Sc alloy,the wear loss of samples with Sc is greatly decreased,and wear resistance is increased with increasing content of Sc.The experimental results indicate that the combination of good mechanical properties,corrosion resistance and tribological properties of Zr-8.8Si-(5,10 and 15 at.%)Sc alloys was much better than Zr-8.8Si-0Sc alloy.Among them,the comprehensive property of Zr-8.8Si-10Sc alloy is preferable in this work.
基金Q.Li acknowledges National Natural Science Foundation of China(No.U2102212)L.Zhang acknowledges the Natural Science Foundation of Hunan Province for Distinguished Young Scholars(No.2021JJ10062)+5 种基金S.Chen acknowledges the Fundamental Research Funds for the Central Universities of Central South University(No.2019zzts486)S.Yang acknowledges the financial support from the Fundamental Research Funds for the Central Universities of Central South University(No.2019zzts050)Postgraduate Scientific Research Innovation Project of Hunan Province(No.CX20190106)Q.Luo acknowledges the Shanghai Rising-Star Program(No.21QA1403200)W.Xie.acknowledges the financial support of National Science Foundation of China(No.52003150)Eastern Young Scholar at Shanghai Institutions of Higher Learning(No.QD2019006).
文摘In recent years,high-entropy alloys(HEAs)have become a research hotspot in materials community,and great progress has been made in exploring various high-performance HEAs.As a special class,the light-weight refractory high-entropy alloys(RHEAs)own both excellent high-temperature comprehensive properties and low density and have accordingly attracted more and more attention.In this paper,we presented a comprehensive review of the recent progress and status in light-weight RHEAs.Based on an exhausting search of the literature reports,one strategy in terms of phase numbers after preparation was first proposed to classify the light-weight RHEAs into three categories.Then,the status on the fundamental thermodynamic and thermophysical data/databases,computational approaches for alloy designing,and preparation/fabrication techniques of light-weight RHEAs was introduced one after another.After that,the progress on mechanical properties and oxidation/corrosion/wear behaviors of light-weight RHEAs at room and high temperatures was summarized.Finally,the conclusions of this review were drawn.By pointing out the shortcomings of the current research,the follow-up development directions in the field of light-weight RHEAs were also given.
基金National Natural Science Foundation of China(62174148)National Key Research and Development Program(2022YFE0112000,2016YFE0118400)+2 种基金Key Program for International Joint Research of Henan Province(231111520300)Ningbo Major Project of“Science,Technology and Innovation 2025”(2019B10129)Zhengzhou 1125 Innovation Project(ZZ2018-45)。
基金supported financially by the National Natural Science Foundation of China(Nos.51971040,51701029 and 51531002)the National Key Research and Development Program of China(No.2016YFB0301100)+3 种基金the Chongqing Research Program of Basic Research and Frontier Technology(No.cstc2016jcyjA0388)the China Postdoctoral Science Foundation Funded Project(Nos.2017M620410 and 2018T110942)the Chongqing Postdoctoral Scientific Research Foundation(No.Xm2017010)the Fundamental Research Funds for the Central Universities(No.2018CDGFCL005).
文摘Anodic oxidation is a prevalent technique to introduce superior corrosion and wear resistance upon the surface of titanium(Ti)alloys,in which the selection of appropriate electrolytes and defect-sealing strategies is a key.This study aims to address such issues through anodizing Ti-10V-2Fe-3Al alloy in malic acid,followed by a post-sealing treatment with Mg-Al layered double hydroxides(LDHs).The characteristics of the samples were investigated using scanning electron microscopy(SEM),atomic force microscopy(AFM),glow discharge optical emission spectroscopy(GDOES),X-ray diffraction(XRD)and energy-dispersive X-ray spectroscopy(EDS).SEM micrographs reveals that the anodic coating had a surface full of bulges and cracks,and was almost sealed by the following LDHs treatment.XRD pattern indicate that the anodic coating was mainly consisted of amorphous TiO2 with a small fraction of anatase,but its crystallization degree was increased through the post-sealing.Moreover,electrochemical and tribological measurements demonstrate that corrosion current density was 2.8×10-6,2.0×10-7,5.9×10-9A cm-2,and wear rate was 1.45×10-3,1.30×10-4 and 6.90×10-5 mm3 N-1 m-1 for respective bare Ti-10V-2Fe-3Al alloy substrate,anodized specimens without and with the LDHs post treatment.Finally,a plausible wear mechanism was proposed.
