The effect of heat treatments on laser additive manufacturing(LAM)Ti-5Al-2Sn-2Zr-4Mo-4Cr titanium alloy(TC17)was studied aiming to optimize its microstructure and mechanical properties.The as-deposited sample exhibits...The effect of heat treatments on laser additive manufacturing(LAM)Ti-5Al-2Sn-2Zr-4Mo-4Cr titanium alloy(TC17)was studied aiming to optimize its microstructure and mechanical properties.The as-deposited sample exhibits features of a mixed priorβgrain structure consisting of equiaxed and columnar grains,intragranular ultra-fineαlaths and numerous continuous grain boundaryα(αGB).After being pre-annealed inα+βregion(840°C)and standard solution and aging treated,the continuousαGB becomes coarser and the precipitate free zone(PFZ)nearby theαGB transforms into a zone filled with ultra-fine secondaryα(αS)but no primaryα(αP).When pre-annealed in singleβregion(910°C),allαphases transform intoβphase and the alloying elements distribute uniformly near the grain boundary.DiscontinuousαGB and uniform mixture ofαP andαS near grain boundary form after subsequent solution and aging treatment.The two heat treatments can improve the tensile mechanical properties of LAM TC17to satisfy the aviation standard for TC17.展开更多
Single-layer and multilayer laser additive manufacturing(LAM)for TC11 alloy with different Nd additions was conducted and the effect of Nd addition on microstructure and properties was studied.With the addition of Nd,...Single-layer and multilayer laser additive manufacturing(LAM)for TC11 alloy with different Nd additions was conducted and the effect of Nd addition on microstructure and properties was studied.With the addition of Nd,the aspect ratio of melting pools of single-layer specimens increases and the columnar-to-equiaxed transition occurs.The originalβgrain size andαplate width of TC11−1.0Nd are significantly reduced compared with those of pure TC11 specimens.It is proposed that the evenly distributed fine Nd_(2)O_(3) precipitates of about 1.51μm are formed preferentially during rapid solidification of melting pool,and they serve as heterogeneous nucleation particles to refine the microstructure in the subsequent solidification and solid-state phase transformation.Due to the multiple effects of Nd on the microstructure,the ultimate tensile strength of TC11−1.0Nd increases,while the yield strength,ductility and microhardness decrease compared with those of pure TC11.展开更多
Wire arc additive manufacturing(WAAM)is a novel manufacturing technique by which high strength metal components can be fabricated layer by layer using an electric arc as the heat source and metal wire as feedstock,and...Wire arc additive manufacturing(WAAM)is a novel manufacturing technique by which high strength metal components can be fabricated layer by layer using an electric arc as the heat source and metal wire as feedstock,and offers the potential to produce large dimensional structures at much higher build rate and minimum waste of raw material.In the present work,a cold metal transfer(CMT)based additive manufacturing was carried out and the effect of deposition rate on the microstructure and mechanical properties of WAAM Ti-6Al-4V components was investigated.The microstructure of WAAM components showed similar microstructural morphology in all deposition conditions.When the deposition rate increased from 1.63 to 2.23 kg/h,the ultimate tensile strength(UTS)decreased from 984.6 MPa to 899.2 MPa and the micro-hardness showed a scattered but clear decline trend.展开更多
From the perspective of biomechanics and forming technology,Ti−Fe−Zr−Sn−Y eutectic alloy was designed using a“cluster-plus-glue-atom”model,and then the alloy was prepared by laser additive manufacturing(LAM)on pure ...From the perspective of biomechanics and forming technology,Ti−Fe−Zr−Sn−Y eutectic alloy was designed using a“cluster-plus-glue-atom”model,and then the alloy was prepared by laser additive manufacturing(LAM)on pure titanium substrate.The mechanical properties of the alloy were evaluated using micro-hardness and compression tester,and the elastic modulus was measured by nanoindenter.The results show that the alloy exhibits a high hardness of HV(788±10),a high strength of 2229 MPa,a failure strain of 14%,and a low elastic modulus of 87.5 GPa.The alloy also has good tribological,chemical,forming,and biological properties.The comprehensive performances of the Ti64.51Fe26.40Zr5.86Sn2.93Y0.30 alloy are superior to those of the Ti70.5Fe29.5 eutectic alloy and commercial Ti−6Al−4V alloy.All the above-mentioned qualities make the alloy a promising candidate as LAM biomaterial.展开更多
As the next generation biomedical titanium alloy, β-type titanium alloys are excellent candidates for biomedical applications due to the relative low elastic modulus and the contained non-toxic elements. However, the...As the next generation biomedical titanium alloy, β-type titanium alloys are excellent candidates for biomedical applications due to the relative low elastic modulus and the contained non-toxic elements. However, the relative low strength and unsatisfactory tribological property are undesired for load-bearing implant applications. In this study, 0-5 at% Si was added to the classic Ti-35Nb-5Ta-7Zr alloy to improve its strength and wear resistance, and the(Ti-35Nb-5Ta-7Zr)1-x-Six(x=0, 1 at% and 5 at%) alloy were fabricated by selective electron beam melting(SEBM)technology. The results indicated that Si addition significantly increases in compressive yield strength, which is mainly due to grain refinement strengthening. At the same time, the wear rate of the as-built TNTZ-5Si alloy in SBF solution was only ~30% of the Ti-6Al-4V alloy. Consequently, the TNTZ-5Si alloy showed an excellent combination of compressive yield strength, elastic modulus and wear resistance for potential load-bearing implant applications.展开更多
基金Project(BX201600010) supported by the National Postdoctoral Program for Innovative Talents of ChinaProject(2015QNRC001) supported by the Young Elite Scientist Sponsorship Program of China
文摘The effect of heat treatments on laser additive manufacturing(LAM)Ti-5Al-2Sn-2Zr-4Mo-4Cr titanium alloy(TC17)was studied aiming to optimize its microstructure and mechanical properties.The as-deposited sample exhibits features of a mixed priorβgrain structure consisting of equiaxed and columnar grains,intragranular ultra-fineαlaths and numerous continuous grain boundaryα(αGB).After being pre-annealed inα+βregion(840°C)and standard solution and aging treated,the continuousαGB becomes coarser and the precipitate free zone(PFZ)nearby theαGB transforms into a zone filled with ultra-fine secondaryα(αS)but no primaryα(αP).When pre-annealed in singleβregion(910°C),allαphases transform intoβphase and the alloying elements distribute uniformly near the grain boundary.DiscontinuousαGB and uniform mixture ofαP andαS near grain boundary form after subsequent solution and aging treatment.The two heat treatments can improve the tensile mechanical properties of LAM TC17to satisfy the aviation standard for TC17.
基金financially supported by the National Natural Science Foundation of China(Nos.51801009,52071005)the Youth Talent Support Program of Beihang University,China(No.YWF-21-BJ-J-1143)Shuangyiliu Fund of Beihang University,China(No.030810)。
文摘Single-layer and multilayer laser additive manufacturing(LAM)for TC11 alloy with different Nd additions was conducted and the effect of Nd addition on microstructure and properties was studied.With the addition of Nd,the aspect ratio of melting pools of single-layer specimens increases and the columnar-to-equiaxed transition occurs.The originalβgrain size andαplate width of TC11−1.0Nd are significantly reduced compared with those of pure TC11 specimens.It is proposed that the evenly distributed fine Nd_(2)O_(3) precipitates of about 1.51μm are formed preferentially during rapid solidification of melting pool,and they serve as heterogeneous nucleation particles to refine the microstructure in the subsequent solidification and solid-state phase transformation.Due to the multiple effects of Nd on the microstructure,the ultimate tensile strength of TC11−1.0Nd increases,while the yield strength,ductility and microhardness decrease compared with those of pure TC11.
基金Projects(52075317,51905333)supported by the National Natural Science Foundation of ChinaProject(IEC\NSFC\181278)supported by the Royal Society through International Exchanges 2018 Cost Share(China)Scheme+2 种基金Project(19YF1418100)supported by Shanghai Sailing Program,ChinaProjects(19511106400,19511106402)supported by Shanghai Science and Technology Committee Innovation,ChinaProject(19030501300)supported by Shanghai Local Colleges and Universities Capacity Building Special Plan,China。
文摘Wire arc additive manufacturing(WAAM)is a novel manufacturing technique by which high strength metal components can be fabricated layer by layer using an electric arc as the heat source and metal wire as feedstock,and offers the potential to produce large dimensional structures at much higher build rate and minimum waste of raw material.In the present work,a cold metal transfer(CMT)based additive manufacturing was carried out and the effect of deposition rate on the microstructure and mechanical properties of WAAM Ti-6Al-4V components was investigated.The microstructure of WAAM components showed similar microstructural morphology in all deposition conditions.When the deposition rate increased from 1.63 to 2.23 kg/h,the ultimate tensile strength(UTS)decreased from 984.6 MPa to 899.2 MPa and the micro-hardness showed a scattered but clear decline trend.
基金Project(51371041)supported by the National Natural Science Foundation of China。
文摘From the perspective of biomechanics and forming technology,Ti−Fe−Zr−Sn−Y eutectic alloy was designed using a“cluster-plus-glue-atom”model,and then the alloy was prepared by laser additive manufacturing(LAM)on pure titanium substrate.The mechanical properties of the alloy were evaluated using micro-hardness and compression tester,and the elastic modulus was measured by nanoindenter.The results show that the alloy exhibits a high hardness of HV(788±10),a high strength of 2229 MPa,a failure strain of 14%,and a low elastic modulus of 87.5 GPa.The alloy also has good tribological,chemical,forming,and biological properties.The comprehensive performances of the Ti64.51Fe26.40Zr5.86Sn2.93Y0.30 alloy are superior to those of the Ti70.5Fe29.5 eutectic alloy and commercial Ti−6Al−4V alloy.All the above-mentioned qualities make the alloy a promising candidate as LAM biomaterial.
基金Project(2019zdzx-04-03) supported by the Science&Technology Specific Projects of Shaanxi Province,ChinaProject(2021KJXX-75) supported by the Innovation Capability Support Plan of Shaanxi Province,China。
文摘As the next generation biomedical titanium alloy, β-type titanium alloys are excellent candidates for biomedical applications due to the relative low elastic modulus and the contained non-toxic elements. However, the relative low strength and unsatisfactory tribological property are undesired for load-bearing implant applications. In this study, 0-5 at% Si was added to the classic Ti-35Nb-5Ta-7Zr alloy to improve its strength and wear resistance, and the(Ti-35Nb-5Ta-7Zr)1-x-Six(x=0, 1 at% and 5 at%) alloy were fabricated by selective electron beam melting(SEBM)technology. The results indicated that Si addition significantly increases in compressive yield strength, which is mainly due to grain refinement strengthening. At the same time, the wear rate of the as-built TNTZ-5Si alloy in SBF solution was only ~30% of the Ti-6Al-4V alloy. Consequently, the TNTZ-5Si alloy showed an excellent combination of compressive yield strength, elastic modulus and wear resistance for potential load-bearing implant applications.