An efficient and safe hydrogen storage method is one of the important links for the large-scale development of hydrogen in the future. Because of its low price and simple design, Ti-based hydrogen storage alloys are c...An efficient and safe hydrogen storage method is one of the important links for the large-scale development of hydrogen in the future. Because of its low price and simple design, Ti-based hydrogen storage alloys are considered to be suitable for practical applications. In this paper, we review the latest research on Ti-based hydrogen storage alloys. Firstly, the machine learning and density functional theory are introduced to provide theoretical guidance for the optimization of Ti-based hydrogen storage alloys. Then, in order to improve the hydrogen storage performance, we briefly introduce the research of AB type and AB2 type Ti-based alloys, focusing on doping elements and adaptive after treatment. Finally, suggestions for the future research and development of Ti-based hydrogen storage alloys are proposed. .展开更多
Commercially pure titanium and titanium alloys have been among the most commonly used materials for biomedical applications since the 1950 s.Due to the excellent mechanical tribological properties,corrosion resistance...Commercially pure titanium and titanium alloys have been among the most commonly used materials for biomedical applications since the 1950 s.Due to the excellent mechanical tribological properties,corrosion resistance,biocompatibility,and antibacterial properties of titanium,it is getting much attention as a biomaterial for implants.Furthermore,titanium promotes osseointegration without any additional adhesives by physically bonding with the living bone at the implant site.These properties are crucial for producing high-strength metallic alloys for biomedical applications.Titanium alloys are manufactured into the three types ofα,β,andα+β.The scientific and clinical understanding of titanium and its potential applications,especially in the biomedical field,are still in the early stages.This review aims to establish a credible platform for the current and future roles of titanium in biomedicine.We first explore the developmental history of titanium.Then,we review the recent advancement of the utility of titanium in diverse biomedical areas,its functional properties,mechanisms of biocompatibility,host tissue responses,and various relevant antimicrobial strategies.Future research will be directed toward advanced manufacturing technologies,such as powder-based additive manufacturing,electron beam melting and laser melting deposition,as well as analyzing the effects of alloying elements on the biocompatibility,corrosion resistance,and mechanical properties of titanium.Moreover,the role of titania nanotubes in regenerative medicine and nanomedicine applications,such as localized drug delivery system,immunomodulatory agents,antibacterial agents,and hemocompatibility,is investigated,and the paper concludes with the future outlook of titanium alloys as biomaterials.展开更多
Metallic implants are widely used in internal fixation of bone fracture in surgical treatment.They are mainly used for providing mechanical support and stability during bone reunion,which usually takes a few months to...Metallic implants are widely used in internal fixation of bone fracture in surgical treatment.They are mainly used for providing mechanical support and stability during bone reunion,which usually takes a few months to complete.Conventional implants made of stainless steels,Ti-based alloys and CoCrMo alloys have been widely used for orthopedic reconstruction due to their high strength and high corrosion resistance.Such metallic implants will remain permanently inside the body after implantation,and a second surgery after bone healing is needed because the long-term presence of implant will lead to various problems.An implant removal surgery not only incurs expenditure,but also risk and psychological burden.As a consequence,studies on the development of biodegradable implants,which would degrade and disappear in vivo after bone reunion is completed,have drawn researchers’attention.In this connection,Mg-based alloys have shown great potentials as promising implant materials mainly due to their low density,inherent biocompatibility,biodegradability and mechanical properties close to those of bone.However,the high degradation rate of Mg-based implants in vivo is the biggest hurdle to overcome.Apart from materials selection,a fixation implant is ideally tailor-made in size and shape for an individual case,for best surgical outcomes.Therefore,laser additive manufacturing(LAM),with the advent of sophisticated laser systems and software,is an ideal process to solve these problems.In this paper,we reviewed the progress in LAM of biodegradable Mg-based alloys for biomedical applications.The effect of powder properties and laser processing parameter on the formability and quality was thoroughly discussed.The microstructure,phase constituents and metallurgical defects formed in the LAMed samples were delineated.The mechanical properties,corrosion resistance,biocompatibility and antibacterial properties of the LAMed samples were summarized and compared with samples fabricated by traditional processes.In addition,we have made some suggestions for advancing the knowledge in the LAM of Mg-based alloys for biomedical implants.展开更多
Microstructure and texture of Ti-Nb-Si based alloys, prepared by water quenching from β-phase field, cold rolling and recrystallization heat treatment followed by water quenching, were investigated in terms of optica...Microstructure and texture of Ti-Nb-Si based alloys, prepared by water quenching from β-phase field, cold rolling and recrystallization heat treatment followed by water quenching, were investigated in terms of optical microstructure and analysis of X-ray pole figure result. In as-quenched sample, relatively random distribution of pole figure was detected without showing a specific texture component. In as-cold rolled sample, however, it is found well-developed several texture components consisting of rotated cube, α-fiber and γ-fiber texture components which are frequently observed in bcc-structured metals and alloys were found. Therefore, texture components developed in the present alloys are closely related to the deformation of β-phase even though small amount of α″ phase co-exist in the microstructure. In recrystallized sample, α-fiber texture component is weakly detected while the other texture components, rotated cube and γ-fiber components, appears to be relatively unchanged. No additional texture components were detected besides those texture components observed in the cold rolled samples.展开更多
Diamond-like carbon （DLC） films were successfully deposited on Ti- 50.8 at% Ni using plasma based ion implantation （PBII） technique. The influence of the pulsed negative bias voltage applied to the substrate from...Diamond-like carbon （DLC） films were successfully deposited on Ti- 50.8 at% Ni using plasma based ion implantation （PBII） technique. The influence of the pulsed negative bias voltage applied to the substrate from 12 kV to 40 kV on the microstracture, nano-indentation hardness and Young＇ s modulus, the surface characteristics and corrosion resistant property as well as hemocompatibility were investigated. The experimental resalts showed that C 1 s peak depended heavily on the bias voltage. With the increase of bias voltage, the ratio of sp2 / sp3 first decreased, reaching a minimum value at 20 kV, and then increased. The DLC coating deposited at 20 kV showed the highest hardness and elastic modulus values as a result of lower sp2/sp3 ratio. The RMS values first decreased from 7.202nm（12 kV） to 5.279 nm（20 kV）, and then increased to 11.449 nm（30 kV） and 7.060 nm（ 40 kV）. The uncoated TiNi alloy showed severe pitting corrosion, due to the presence of Cl-ions in the solution. On the contrary, the DLC coated sample showed very little pitting corrosion and behaved better corrosion resistant property especially for the specimens deposited at 20 kV bias voltages. The platelet adhesion test show that the hemocompatibility of DLC coated TiNi alloy is much better than that of bare TiNi alloy, and the hemocompatibility performance of DLC coated TiNi alloy deposited at 20 kV is superior to that of other coated specimens.展开更多
Nitrogen processed, cold sprayed commercially pure(CP)-Al coatings on Mg-based alloys mostly lack acceptable hardness, wear resistance and most importantly are highly susceptible to localized corrosion in chloride con...Nitrogen processed, cold sprayed commercially pure(CP)-Al coatings on Mg-based alloys mostly lack acceptable hardness, wear resistance and most importantly are highly susceptible to localized corrosion in chloride containing solutions. In this research, commercially pure α-Ti top coating having good pitting potential(~1293 mV_(SCE)), high microhardness(HV_(0.025): 263.03) and low wear rate was applied on a CP-Al coated Mg-based alloy using high pressure cold spray technology. Potentiodynamic polarization(PDP) curves indicated that the probability of transition from metastable pits to the stable pits for cold spayed(CS) Al coating is considerably higher compared to that with the CS Ti top coating(for Ti/Al/Mg system). In addition, CS Ti top coating was in the passivation region in most pH ranges even after 48 h immersion in 3.5 wt% NaCl solution. The stored energy in the CS Ti top coating(as a passive metal) was presumed to be responsible for the easy passivation. Immersion tests indicated no obvious pits formation on the intact CS Ti top coating surface and revealed effective corrosion protection performance of the CS double layered noble barrier coatings on Mg alloys in 3.5 wt% NaCl solution even after 264 h.展开更多
Ti is regarded as one of the promising grain refiners in cast Al-Li-Cu alloys,but few research works have been done on its independent role.In this study,the effect of Ti on the microstructure evolution and mechanical...Ti is regarded as one of the promising grain refiners in cast Al-Li-Cu alloys,but few research works have been done on its independent role.In this study,the effect of Ti on the microstructure evolution and mechanical properties of cast Al-2Li-2Cu-0.5Mg base alloy was investigated.The results revealed that the grains can be prominently refined with the increase of Ti addition.After adding Ti,high density TiB_(2)-Al_(3)Ti composite particles with a low lattice misfit form as heterogeneous nucleation sites for the α-Al matrix.δ’(Al3Li) and T_(1)(Al_(2)CuLi) precipitates that provide enhanced strength are dominated in the alloys after T6 aging treatment.The average size of both δ’ and half-width of δ’-precipitation free zone(PFZ) decreases gradually with the increase of Ti content.This is because the higher binding energy between Ti atoms and vacancies limits the diffusion efficiency of Li atoms,and thus results in a higher ductility.Additionally,no nano-sized Al_(3)Ti or core-shell structure of Al_(3)(Li,Ti) particles are found.The tensile property test results indicate that the Al-2Li-2Cu-0.5Mg alloy achieves optimal properties after aging at 175 °C for 32 h when 0.15wt.% Ti is added.It exhibits a yield strength of 352±5 MPa,an ultimate tensile strength of 423±6 MPa,and an elongation of(3±0.4)%.These findings are expected to offer a reliable theoretical guidance for the industrial composition design of the Al-Li-Cu series cast alloys.展开更多
文摘An efficient and safe hydrogen storage method is one of the important links for the large-scale development of hydrogen in the future. Because of its low price and simple design, Ti-based hydrogen storage alloys are considered to be suitable for practical applications. In this paper, we review the latest research on Ti-based hydrogen storage alloys. Firstly, the machine learning and density functional theory are introduced to provide theoretical guidance for the optimization of Ti-based hydrogen storage alloys. Then, in order to improve the hydrogen storage performance, we briefly introduce the research of AB type and AB2 type Ti-based alloys, focusing on doping elements and adaptive after treatment. Finally, suggestions for the future research and development of Ti-based hydrogen storage alloys are proposed. .
基金supported by the University of Malaya(UM)Research Grant:(FRGS/1/2020/TK0/UM/02/40)。
文摘Commercially pure titanium and titanium alloys have been among the most commonly used materials for biomedical applications since the 1950 s.Due to the excellent mechanical tribological properties,corrosion resistance,biocompatibility,and antibacterial properties of titanium,it is getting much attention as a biomaterial for implants.Furthermore,titanium promotes osseointegration without any additional adhesives by physically bonding with the living bone at the implant site.These properties are crucial for producing high-strength metallic alloys for biomedical applications.Titanium alloys are manufactured into the three types ofα,β,andα+β.The scientific and clinical understanding of titanium and its potential applications,especially in the biomedical field,are still in the early stages.This review aims to establish a credible platform for the current and future roles of titanium in biomedicine.We first explore the developmental history of titanium.Then,we review the recent advancement of the utility of titanium in diverse biomedical areas,its functional properties,mechanisms of biocompatibility,host tissue responses,and various relevant antimicrobial strategies.Future research will be directed toward advanced manufacturing technologies,such as powder-based additive manufacturing,electron beam melting and laser melting deposition,as well as analyzing the effects of alloying elements on the biocompatibility,corrosion resistance,and mechanical properties of titanium.Moreover,the role of titania nanotubes in regenerative medicine and nanomedicine applications,such as localized drug delivery system,immunomodulatory agents,antibacterial agents,and hemocompatibility,is investigated,and the paper concludes with the future outlook of titanium alloys as biomaterials.
基金fully supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region(152131/18E).
文摘Metallic implants are widely used in internal fixation of bone fracture in surgical treatment.They are mainly used for providing mechanical support and stability during bone reunion,which usually takes a few months to complete.Conventional implants made of stainless steels,Ti-based alloys and CoCrMo alloys have been widely used for orthopedic reconstruction due to their high strength and high corrosion resistance.Such metallic implants will remain permanently inside the body after implantation,and a second surgery after bone healing is needed because the long-term presence of implant will lead to various problems.An implant removal surgery not only incurs expenditure,but also risk and psychological burden.As a consequence,studies on the development of biodegradable implants,which would degrade and disappear in vivo after bone reunion is completed,have drawn researchers’attention.In this connection,Mg-based alloys have shown great potentials as promising implant materials mainly due to their low density,inherent biocompatibility,biodegradability and mechanical properties close to those of bone.However,the high degradation rate of Mg-based implants in vivo is the biggest hurdle to overcome.Apart from materials selection,a fixation implant is ideally tailor-made in size and shape for an individual case,for best surgical outcomes.Therefore,laser additive manufacturing(LAM),with the advent of sophisticated laser systems and software,is an ideal process to solve these problems.In this paper,we reviewed the progress in LAM of biodegradable Mg-based alloys for biomedical applications.The effect of powder properties and laser processing parameter on the formability and quality was thoroughly discussed.The microstructure,phase constituents and metallurgical defects formed in the LAMed samples were delineated.The mechanical properties,corrosion resistance,biocompatibility and antibacterial properties of the LAMed samples were summarized and compared with samples fabricated by traditional processes.In addition,we have made some suggestions for advancing the knowledge in the LAM of Mg-based alloys for biomedical implants.
文摘Microstructure and texture of Ti-Nb-Si based alloys, prepared by water quenching from β-phase field, cold rolling and recrystallization heat treatment followed by water quenching, were investigated in terms of optical microstructure and analysis of X-ray pole figure result. In as-quenched sample, relatively random distribution of pole figure was detected without showing a specific texture component. In as-cold rolled sample, however, it is found well-developed several texture components consisting of rotated cube, α-fiber and γ-fiber texture components which are frequently observed in bcc-structured metals and alloys were found. Therefore, texture components developed in the present alloys are closely related to the deformation of β-phase even though small amount of α″ phase co-exist in the microstructure. In recrystallized sample, α-fiber texture component is weakly detected while the other texture components, rotated cube and γ-fiber components, appears to be relatively unchanged. No additional texture components were detected besides those texture components observed in the cold rolled samples.
文摘Diamond-like carbon （DLC） films were successfully deposited on Ti- 50.8 at% Ni using plasma based ion implantation （PBII） technique. The influence of the pulsed negative bias voltage applied to the substrate from 12 kV to 40 kV on the microstracture, nano-indentation hardness and Young＇ s modulus, the surface characteristics and corrosion resistant property as well as hemocompatibility were investigated. The experimental resalts showed that C 1 s peak depended heavily on the bias voltage. With the increase of bias voltage, the ratio of sp2 / sp3 first decreased, reaching a minimum value at 20 kV, and then increased. The DLC coating deposited at 20 kV showed the highest hardness and elastic modulus values as a result of lower sp2/sp3 ratio. The RMS values first decreased from 7.202nm（12 kV） to 5.279 nm（20 kV）, and then increased to 11.449 nm（30 kV） and 7.060 nm（ 40 kV）. The uncoated TiNi alloy showed severe pitting corrosion, due to the presence of Cl-ions in the solution. On the contrary, the DLC coated sample showed very little pitting corrosion and behaved better corrosion resistant property especially for the specimens deposited at 20 kV bias voltages. The platelet adhesion test show that the hemocompatibility of DLC coated TiNi alloy is much better than that of bare TiNi alloy, and the hemocompatibility performance of DLC coated TiNi alloy deposited at 20 kV is superior to that of other coated specimens.
基金the financial support from the Fundamental Research Program of Shanxi Province,China(No.202203021211130)the National Natural Science Foundation of China(Nos.51801132,52075359)。
基金the financial support received from the National Science Foundation (NSF-CMMI 2131441) under the direction of Dr.Alexis Lewis。
文摘Nitrogen processed, cold sprayed commercially pure(CP)-Al coatings on Mg-based alloys mostly lack acceptable hardness, wear resistance and most importantly are highly susceptible to localized corrosion in chloride containing solutions. In this research, commercially pure α-Ti top coating having good pitting potential(~1293 mV_(SCE)), high microhardness(HV_(0.025): 263.03) and low wear rate was applied on a CP-Al coated Mg-based alloy using high pressure cold spray technology. Potentiodynamic polarization(PDP) curves indicated that the probability of transition from metastable pits to the stable pits for cold spayed(CS) Al coating is considerably higher compared to that with the CS Ti top coating(for Ti/Al/Mg system). In addition, CS Ti top coating was in the passivation region in most pH ranges even after 48 h immersion in 3.5 wt% NaCl solution. The stored energy in the CS Ti top coating(as a passive metal) was presumed to be responsible for the easy passivation. Immersion tests indicated no obvious pits formation on the intact CS Ti top coating surface and revealed effective corrosion protection performance of the CS double layered noble barrier coatings on Mg alloys in 3.5 wt% NaCl solution even after 264 h.
基金financially supported by the National Natural Science Foundation of China (Nos.51821001 and 51871148)。
文摘Ti is regarded as one of the promising grain refiners in cast Al-Li-Cu alloys,but few research works have been done on its independent role.In this study,the effect of Ti on the microstructure evolution and mechanical properties of cast Al-2Li-2Cu-0.5Mg base alloy was investigated.The results revealed that the grains can be prominently refined with the increase of Ti addition.After adding Ti,high density TiB_(2)-Al_(3)Ti composite particles with a low lattice misfit form as heterogeneous nucleation sites for the α-Al matrix.δ’(Al3Li) and T_(1)(Al_(2)CuLi) precipitates that provide enhanced strength are dominated in the alloys after T6 aging treatment.The average size of both δ’ and half-width of δ’-precipitation free zone(PFZ) decreases gradually with the increase of Ti content.This is because the higher binding energy between Ti atoms and vacancies limits the diffusion efficiency of Li atoms,and thus results in a higher ductility.Additionally,no nano-sized Al_(3)Ti or core-shell structure of Al_(3)(Li,Ti) particles are found.The tensile property test results indicate that the Al-2Li-2Cu-0.5Mg alloy achieves optimal properties after aging at 175 °C for 32 h when 0.15wt.% Ti is added.It exhibits a yield strength of 352±5 MPa,an ultimate tensile strength of 423±6 MPa,and an elongation of(3±0.4)%.These findings are expected to offer a reliable theoretical guidance for the industrial composition design of the Al-Li-Cu series cast alloys.
