A new kind offl biomedical titanium alloy, Ti-35Nb-4Sn-6Mo-9Zr, composed of non-toxic elements Nb, Mo, Zr and Sn with lower elastic modulus and higher strength was designed based on d-electron alloy design theory and ...A new kind offl biomedical titanium alloy, Ti-35Nb-4Sn-6Mo-9Zr, composed of non-toxic elements Nb, Mo, Zr and Sn with lower elastic modulus and higher strength was designed based on d-electron alloy design theory and JMatPro software using orthogonal experiment. The microstructure and basic mechanical properties of designed alloy were investigated. The results show that the alloy is composed of single fl equiaxed grains after solution treatment at 800 ~C. Compared with Ti-6A1-4V, the mechanical properties of the designed alloy are more excellent： E=65 GPa, σb=834 MPa, σ0.2=802 MPa, and σ=11%, which is expected to become a promising new type implanted material. The research approach adopted can reduce the experimental time and cost effectively, and get the ideal experimental results.展开更多
A theoretical prediction on forming limit diagram（FLD） of AZ31 magnesium alloy sheet was developed at warm temperatures based on the M-K theory. Two different yield criteria of von Mises and Hill＇48 were applied in...A theoretical prediction on forming limit diagram（FLD） of AZ31 magnesium alloy sheet was developed at warm temperatures based on the M-K theory. Two different yield criteria of von Mises and Hill＇48 were applied in this model. Mechanical properties of AZ31 magnesium alloy used in the prediction were obtained by uniaxial tensile tests and the Fields-Backofen equation was incorporated in the analysis. In addition, experimental FLDs of AZ31 were acquired by conducting rigid die swell test at different temperatures to verify the prediction. It is demonstrated from a comparison between the predicted and the experimental FLDs at 473 K and 523 K that the predicted results are influenced by the type of yield criterion used in the calculation, especially at lower temperatures. Furthermore, a better agreement between the predicted results and experimental data for AZ31 magnesium alloy sheet at warm temperatures was obtained when Hill＇48 yield criterion was applied.展开更多
Micro-alloying design of wrought magnesium(Mg) alloys is an important strategy to achieve high mechanical properties at a low cost. In the last two decades, significant progress has been made from both theory and expe...Micro-alloying design of wrought magnesium(Mg) alloys is an important strategy to achieve high mechanical properties at a low cost. In the last two decades, significant progress has been made from both theory and experiment. In the present review, we try to summarize recent advances in micro-alloying design of wrought Mg alloys from both theoretical and pragmatic perspectives, and provide fundamental data required for establishing the relationship between chemical composition and mechanical properties of Mg alloys. We start with theoretical attempts for understanding the mechanical properties of Mg alloys at different scales, by involving first principle calculations,molecular dynamics, cellular automata, and crystal plasticity. Then, the role of alloying elements is discussed for a series of promising Mg alloys such as Mg-Al, Mg-Zn, Mg-RE(rare-earth element), Mg-Sn, and Mg-Ca families.Potential challenges in the micro-alloying design of Mg alloys are highlighted at the end. The review is expected to provide helpful guidance for the intelligent design of novel wrought Mg alloys and inspire more innovative ideas in this field.展开更多
In order to find out the impact of aluminum alloy hub replaced by the magnesium alloy hub on environment,the resource consumption,energy consumption and pollutant emission during hub production and their service life ...In order to find out the impact of aluminum alloy hub replaced by the magnesium alloy hub on environment,the resource consumption,energy consumption and pollutant emission during hub production and their service life of the two types of hubs are investigated based on the life cycle assessment(LCA)theory.The results indicate that the adverse impact on environment can be effectively reduced by the application of magnesium alloy hubs.Compared with aluminum alloy hubs,the global warming potential(GWP)and human toxicity potential(HTP)are reduced by 39.6%and 24.0%,respectively.CO2 is the main pollutant in the life cycles of the two kinds of hubs,which is generated throughout the whole life cycle including the fabrication process and the service life,while the pollutants of particles mainly come from the fabrication stage.Compared with the aluminum alloy hubs,the green effect brought by magnesium alloy hubs is mainly due to the reduction of fuel consumption caused by weight loss.展开更多
High entropy alloys(HEAs)have been the star materials in electrocatalysis research in recent years.One of their key features is the greatly increased multiplicity of active sites compared to conventional catalytic mat...High entropy alloys(HEAs)have been the star materials in electrocatalysis research in recent years.One of their key features is the greatly increased multiplicity of active sites compared to conventional catalytic materials.This increased multiplicity stimulates a cocktail effect and a scaling-relation breaking effect,and results in improved activity.However,the multiplicity of active sites in HEAs also poses new problems for mechanistic studies.One apparent problem is the inapplicability to HEA catalysts of the currently most popular mechanistic study method,which uses the electrocatalytic theoretical framework(ETF)based on the computational hydrogen electrode(CHE).The ETF uses a single adsorption energy to represent the catalyst,i.e.,a catalyst is represented by a'point'in the volcanic relationship.It naturally does not involve the multiplicity of active sites of a catalyst,and hence loses brevity in expressing the cocktail effect and scaling-relation breaking effect in HEA catalysis.This paper attempts to solve this inapplicability.Based on the fact that the adsorption energy distribution of HEAs is close to a normal distribution,the mean and variance of the adsorption energy distribution are introduced as descriptors of the ETF,replacing the original single adsorption energy.A quantitative relationship between the variance and the cocktail and scaling-relation braking effects is established.We believe the method described in this work will make the ETF more effective in mechanistic studies of HEA electrocatalysis.展开更多
This paper focuses on the thermo-mechanical behaviors of functionally graded(FG)shape memory alloy(SMA)composite beams based on Timoshenko beam theory.The volume fraction of SMA fiber is graded in the thickness of bea...This paper focuses on the thermo-mechanical behaviors of functionally graded(FG)shape memory alloy(SMA)composite beams based on Timoshenko beam theory.The volume fraction of SMA fiber is graded in the thickness of beam according to a power-law function and the equivalent parameters are formulated.The governing differential equations,which can be solved by direct integration,are established by employing the composite laminated plate theory.The influences of FG parameter,ambient temperature and SMA fiber laying angle on the thermo-mechanical behaviors are numerically simulated and discussed under different boundary conditions.Results indicate that the neutral plane does not coincide with the middle plane of the composite beam and the distribution of martensite is asymmetric along the thickness.Both the increments of the functionally graded parameter and ambient temperature make the composite beam become stiffer.However,the influence of the SMA fiber laying angle can be negligent.This work can provide the theoretical basis for the design and application of FG SMA structures.展开更多
基金Project(BE2011778)supported by Science and Technology Support Program of Jiangsu Province,ChinaProject(20133069014)supported by Aeronautical Science Foundation of China
文摘A new kind offl biomedical titanium alloy, Ti-35Nb-4Sn-6Mo-9Zr, composed of non-toxic elements Nb, Mo, Zr and Sn with lower elastic modulus and higher strength was designed based on d-electron alloy design theory and JMatPro software using orthogonal experiment. The microstructure and basic mechanical properties of designed alloy were investigated. The results show that the alloy is composed of single fl equiaxed grains after solution treatment at 800 ~C. Compared with Ti-6A1-4V, the mechanical properties of the designed alloy are more excellent： E=65 GPa, σb=834 MPa, σ0.2=802 MPa, and σ=11%, which is expected to become a promising new type implanted material. The research approach adopted can reduce the experimental time and cost effectively, and get the ideal experimental results.
基金Project(51375328)supported by the National Natural Science Foundation of ChinaProject(20143009)supported by Graduates Innovation Project of Shanxi Province,ChinaProject(2015-036)supported by Shanxi Scholarship Council of China
文摘A theoretical prediction on forming limit diagram（FLD） of AZ31 magnesium alloy sheet was developed at warm temperatures based on the M-K theory. Two different yield criteria of von Mises and Hill＇48 were applied in this model. Mechanical properties of AZ31 magnesium alloy used in the prediction were obtained by uniaxial tensile tests and the Fields-Backofen equation was incorporated in the analysis. In addition, experimental FLDs of AZ31 were acquired by conducting rigid die swell test at different temperatures to verify the prediction. It is demonstrated from a comparison between the predicted and the experimental FLDs at 473 K and 523 K that the predicted results are influenced by the type of yield criterion used in the calculation, especially at lower temperatures. Furthermore, a better agreement between the predicted results and experimental data for AZ31 magnesium alloy sheet at warm temperatures was obtained when Hill＇48 yield criterion was applied.
基金the financial supports from the National Natural Science Foundation of China (Nos. U1764253, U2037601, 52001037, 51971044, 52101126)the National Defense Basic Scientific Research Program of China, China Postdoctoral Science Foundation (No. 2021M700566)+3 种基金the Natural Science Foundation of Chongqing, China (No. cstc2019jcyjmsxm X0234)Chongqing Science and Technology Commission, China (No. cstc2017zdcyzdzx X0006)Chongqing Scientific and Technological Talents Program, China (No. KJXX2017002)Qinghai Science and Technology Program, China (No. 2018-GX-A1)。
文摘Micro-alloying design of wrought magnesium(Mg) alloys is an important strategy to achieve high mechanical properties at a low cost. In the last two decades, significant progress has been made from both theory and experiment. In the present review, we try to summarize recent advances in micro-alloying design of wrought Mg alloys from both theoretical and pragmatic perspectives, and provide fundamental data required for establishing the relationship between chemical composition and mechanical properties of Mg alloys. We start with theoretical attempts for understanding the mechanical properties of Mg alloys at different scales, by involving first principle calculations,molecular dynamics, cellular automata, and crystal plasticity. Then, the role of alloying elements is discussed for a series of promising Mg alloys such as Mg-Al, Mg-Zn, Mg-RE(rare-earth element), Mg-Sn, and Mg-Ca families.Potential challenges in the micro-alloying design of Mg alloys are highlighted at the end. The review is expected to provide helpful guidance for the intelligent design of novel wrought Mg alloys and inspire more innovative ideas in this field.
基金Projects(51605159,51475162)supported by the National Natural Science Foundation of ChinaProject(16B092)supported by the Hunan Education Department Outstanding Youth Foundation,ChinaProject(2016JJ5042)supported by the Natural Science Foundation of Hunan Province,China
文摘In order to find out the impact of aluminum alloy hub replaced by the magnesium alloy hub on environment,the resource consumption,energy consumption and pollutant emission during hub production and their service life of the two types of hubs are investigated based on the life cycle assessment(LCA)theory.The results indicate that the adverse impact on environment can be effectively reduced by the application of magnesium alloy hubs.Compared with aluminum alloy hubs,the global warming potential(GWP)and human toxicity potential(HTP)are reduced by 39.6%and 24.0%,respectively.CO2 is the main pollutant in the life cycles of the two kinds of hubs,which is generated throughout the whole life cycle including the fabrication process and the service life,while the pollutants of particles mainly come from the fabrication stage.Compared with the aluminum alloy hubs,the green effect brought by magnesium alloy hubs is mainly due to the reduction of fuel consumption caused by weight loss.
文摘High entropy alloys(HEAs)have been the star materials in electrocatalysis research in recent years.One of their key features is the greatly increased multiplicity of active sites compared to conventional catalytic materials.This increased multiplicity stimulates a cocktail effect and a scaling-relation breaking effect,and results in improved activity.However,the multiplicity of active sites in HEAs also poses new problems for mechanistic studies.One apparent problem is the inapplicability to HEA catalysts of the currently most popular mechanistic study method,which uses the electrocatalytic theoretical framework(ETF)based on the computational hydrogen electrode(CHE).The ETF uses a single adsorption energy to represent the catalyst,i.e.,a catalyst is represented by a'point'in the volcanic relationship.It naturally does not involve the multiplicity of active sites of a catalyst,and hence loses brevity in expressing the cocktail effect and scaling-relation breaking effect in HEA catalysis.This paper attempts to solve this inapplicability.Based on the fact that the adsorption energy distribution of HEAs is close to a normal distribution,the mean and variance of the adsorption energy distribution are introduced as descriptors of the ETF,replacing the original single adsorption energy.A quantitative relationship between the variance and the cocktail and scaling-relation braking effects is established.We believe the method described in this work will make the ETF more effective in mechanistic studies of HEA electrocatalysis.
文摘This paper focuses on the thermo-mechanical behaviors of functionally graded(FG)shape memory alloy(SMA)composite beams based on Timoshenko beam theory.The volume fraction of SMA fiber is graded in the thickness of beam according to a power-law function and the equivalent parameters are formulated.The governing differential equations,which can be solved by direct integration,are established by employing the composite laminated plate theory.The influences of FG parameter,ambient temperature and SMA fiber laying angle on the thermo-mechanical behaviors are numerically simulated and discussed under different boundary conditions.Results indicate that the neutral plane does not coincide with the middle plane of the composite beam and the distribution of martensite is asymmetric along the thickness.Both the increments of the functionally graded parameter and ambient temperature make the composite beam become stiffer.However,the influence of the SMA fiber laying angle can be negligent.This work can provide the theoretical basis for the design and application of FG SMA structures.
