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
Based on the classic diffusion controlled nucleation and goth theory, the sympathatic nucleation- ledgewise growth mechanism of bainite was studied theoretically for low carbon Fe-C alloys. The rationality of the occu...Based on the classic diffusion controlled nucleation and goth theory, the sympathatic nucleation- ledgewise growth mechanism of bainite was studied theoretically for low carbon Fe-C alloys. The rationality of the occurrence of sympathetic nucleation on the terraces of ledges compating with lateral ledge growth and other sites nucleation was demonstrated by the present work quantita- tively The calculations indicated that low reaction temperatures and high carbon concentrations may favor the sympathetic nucleation, thus accounting for the formation of multilayer structures of bainite.展开更多
The valence electron structures and electron densities on some lattice planes of biomaterials Ti 6Al 4V and Au Pd Pt were calculated by using bond length difference method of the empirical electron theory of solids an...The valence electron structures and electron densities on some lattice planes of biomaterials Ti 6Al 4V and Au Pd Pt were calculated by using bond length difference method of the empirical electron theory of solids and molecules. The results show that there exist the planes with continuous densities in the three crystal cells involved, which verified to some extent the validity of “Atomic Boundary Condition” applying in biomaterials research. It was proposed that the sufficient understanding and reasonable modeling on microstructure of living body are necessary to evaluate directly the electron density continuity between biomaterial and living tissue.展开更多
Time dependent nucleation theory was applied to calculate the incubation time required for α Al nucleation in rapid solidified (RS) Al Fe V Si Nd alloys. The nucleation rates were calculated as a function of tem...Time dependent nucleation theory was applied to calculate the incubation time required for α Al nucleation in rapid solidified (RS) Al Fe V Si Nd alloys. The nucleation rates were calculated as a function of temperature, and the critical cooling rates required for the formation of amorphous α Al at different neodymium concentrations were calculated too. The addition of neodymium increases the amorphizablity of α Al by increasing the incubation time and decreasing the nucleation rate and the critical cooling rate. The calculations are fitted to experimental results when liquidus temperatures are estimated from an approximation, which treats Al Fe V Si Nd as quasi binary Al Fe system.展开更多
The measurements by Huibin XU et al of the stress-dependence ot hysteresis in a NiTi shape memo ry alloy are modeled by catastrophe theory. The cusp catastrophe is used with the strain as the behaviour variable and t...The measurements by Huibin XU et al of the stress-dependence ot hysteresis in a NiTi shape memo ry alloy are modeled by catastrophe theory. The cusp catastrophe is used with the strain as the behaviour variable and the control parameters being functions of the stress and the temperature. A two constant model is found to be preferred to a four constant model.展开更多
The corrosion inhibition behavior of Mg-8Li-3Al alloy in NaCl solution with sodium dodecyl sulfate(SDS)was investigated by hydrogen analysis,scanning electron microscopy(SEM),electrochemical test,scanning Kelvin probe...The corrosion inhibition behavior of Mg-8Li-3Al alloy in NaCl solution with sodium dodecyl sulfate(SDS)was investigated by hydrogen analysis,scanning electron microscopy(SEM),electrochemical test,scanning Kelvin probe force microscopy(SKPFM)and computational methods.Results showed that the corrosion resistance of Mg-8Li-3Al alloy in NaCl solution was effectively improved with SDS.The SEM and SKPFM results confirmed a dense,200 nm-thick SDS-adsorbed layer had formed on the alloy surface.The separation energy ΔE_(gap) and adsorption energy E_(ads) of SDS on the Mg surface were calculated by density functional theory and molecular dynamics simulations,respectively.And the corrosion inhibition mechanism was hypothesized and described.展开更多
The discontinuous yielding phenomenon （DYP） during high temperature deformation was investigated based on the isothermal compression of TC8 titanium alloy. The DYP of TC8 titanium alloy was characterized by quan...The discontinuous yielding phenomenon （DYP） during high temperature deformation was investigated based on the isothermal compression of TC8 titanium alloy. The DYP of TC8 titanium alloy was characterized by quantifying the yield drop of the DYP （△σUL） and ending strain of flow oscillation （εOSC） based on the flow stress？strain curves, and then the effect of deformation parameters on the △σUL and εOSC values was analyzed. The results show that the △σUL and εOSC values increase with the increase of strain rate. The effect of deformation temperature on the ？σUL value depends on the strain rate. Finally, the transmission electron microscope （TEM） observation shows the evidence for the dynamic theory, which ascribes the DYP to the generation of mobile dislocation at the grain boundary. Meanwhile, the optical microscope （OM） observation shows that both the primary α grain and β grain become smaller with the increase of strain, which well interprets the effect of deformation parameters on the △σUL and εOSC values.展开更多
Optical microscope,X-ray diffractometer,scanning electron microscope,tensile tester and dynamic mechanical analyzer(DMA) were applied to investigate the effects of Y and Zn additions on microstructure,mechanical prope...Optical microscope,X-ray diffractometer,scanning electron microscope,tensile tester and dynamic mechanical analyzer(DMA) were applied to investigate the effects of Y and Zn additions on microstructure,mechanical properties and damping capacity of Mg-3Cu-1Mn(CM31) alloy.The results show that with the increase of Y and Zn contents,the secondary dendrite arm spacing of alloys is reduced;meanwhile,the yield strength is increased.In low strain amplitude,the damping capacity of alloys with Y and Zn addition is lower than that of CM31 alloy.However,in strain amplitude over 5×10-3,the damping capacity of alloy with a trace of Y and Zn addition(1%Y and 2%Zn,mass fraction) increases abnormally with the increase of strain amplitude and is near to that of pure Mg,probably due to the increase of dislocation density caused by the precipitation of secondary phase.The temperature dependence of damping capacity of above alloy was also tested and discussed.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.
文摘Based on the classic diffusion controlled nucleation and goth theory, the sympathatic nucleation- ledgewise growth mechanism of bainite was studied theoretically for low carbon Fe-C alloys. The rationality of the occurrence of sympathetic nucleation on the terraces of ledges compating with lateral ledge growth and other sites nucleation was demonstrated by the present work quantita- tively The calculations indicated that low reaction temperatures and high carbon concentrations may favor the sympathetic nucleation, thus accounting for the formation of multilayer structures of bainite.
文摘The valence electron structures and electron densities on some lattice planes of biomaterials Ti 6Al 4V and Au Pd Pt were calculated by using bond length difference method of the empirical electron theory of solids and molecules. The results show that there exist the planes with continuous densities in the three crystal cells involved, which verified to some extent the validity of “Atomic Boundary Condition” applying in biomaterials research. It was proposed that the sufficient understanding and reasonable modeling on microstructure of living body are necessary to evaluate directly the electron density continuity between biomaterial and living tissue.
基金Project supported by the National Natural Science Foundation of China(55791020)
文摘Time dependent nucleation theory was applied to calculate the incubation time required for α Al nucleation in rapid solidified (RS) Al Fe V Si Nd alloys. The nucleation rates were calculated as a function of temperature, and the critical cooling rates required for the formation of amorphous α Al at different neodymium concentrations were calculated too. The addition of neodymium increases the amorphizablity of α Al by increasing the incubation time and decreasing the nucleation rate and the critical cooling rate. The calculations are fitted to experimental results when liquidus temperatures are estimated from an approximation, which treats Al Fe V Si Nd as quasi binary Al Fe system.
文摘The measurements by Huibin XU et al of the stress-dependence ot hysteresis in a NiTi shape memo ry alloy are modeled by catastrophe theory. The cusp catastrophe is used with the strain as the behaviour variable and the control parameters being functions of the stress and the temperature. A two constant model is found to be preferred to a four constant model.
基金the financial support by the National Natural Science Foundation of China(51961026)the Interdisciplinary Innovation Fund of Nanchang University(Project No.2019-9166-27060003)。
文摘The corrosion inhibition behavior of Mg-8Li-3Al alloy in NaCl solution with sodium dodecyl sulfate(SDS)was investigated by hydrogen analysis,scanning electron microscopy(SEM),electrochemical test,scanning Kelvin probe force microscopy(SKPFM)and computational methods.Results showed that the corrosion resistance of Mg-8Li-3Al alloy in NaCl solution was effectively improved with SDS.The SEM and SKPFM results confirmed a dense,200 nm-thick SDS-adsorbed layer had formed on the alloy surface.The separation energy ΔE_(gap) and adsorption energy E_(ads) of SDS on the Mg surface were calculated by density functional theory and molecular dynamics simulations,respectively.And the corrosion inhibition mechanism was hypothesized and described.
基金Project(51275416)supported by the National Natural Science Foundation of China
文摘The discontinuous yielding phenomenon （DYP） during high temperature deformation was investigated based on the isothermal compression of TC8 titanium alloy. The DYP of TC8 titanium alloy was characterized by quantifying the yield drop of the DYP （△σUL） and ending strain of flow oscillation （εOSC） based on the flow stress？strain curves, and then the effect of deformation parameters on the △σUL and εOSC values was analyzed. The results show that the △σUL and εOSC values increase with the increase of strain rate. The effect of deformation temperature on the ？σUL value depends on the strain rate. Finally, the transmission electron microscope （TEM） observation shows the evidence for the dynamic theory, which ascribes the DYP to the generation of mobile dislocation at the grain boundary. Meanwhile, the optical microscope （OM） observation shows that both the primary α grain and β grain become smaller with the increase of strain, which well interprets the effect of deformation parameters on the △σUL and εOSC values.
基金partial financial support from the National Natural Science Foundation of China (No. 52101231)the Science Fund of Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing,China (No. AMGM2021F09)the Natural Science Foundation of Shandong Province,China (No. ZR2021QE044)。
基金Project(10876045) supported by the National Natural Science Foundation of China and China Academy of Engineering PhysicsProject(2007CB613704) supported by the National Basic Research Program of ChinaProject(CSTS2008AB4114) supported by Chongqing Science and Technology Commission,China
文摘Optical microscope,X-ray diffractometer,scanning electron microscope,tensile tester and dynamic mechanical analyzer(DMA) were applied to investigate the effects of Y and Zn additions on microstructure,mechanical properties and damping capacity of Mg-3Cu-1Mn(CM31) alloy.The results show that with the increase of Y and Zn contents,the secondary dendrite arm spacing of alloys is reduced;meanwhile,the yield strength is increased.In low strain amplitude,the damping capacity of alloys with Y and Zn addition is lower than that of CM31 alloy.However,in strain amplitude over 5×10-3,the damping capacity of alloy with a trace of Y and Zn addition(1%Y and 2%Zn,mass fraction) increases abnormally with the increase of strain amplitude and is near to that of pure Mg,probably due to the increase of dislocation density caused by the precipitation of secondary phase.The temperature dependence of damping capacity of above alloy was also tested and discussed.
