采用磁控溅射法在不同V靶功率下制得一系列不同V含量的TiAlVN膜。通过能谱分析、X射线衍射、硬度测量和高温退火研究了V原子分数对Ti Al VN膜成分、晶相结构、硬度和抗高温氧化性能的影响。结果表明,不同V含量的TiAlVN膜均为面心立方结...采用磁控溅射法在不同V靶功率下制得一系列不同V含量的TiAlVN膜。通过能谱分析、X射线衍射、硬度测量和高温退火研究了V原子分数对Ti Al VN膜成分、晶相结构、硬度和抗高温氧化性能的影响。结果表明,不同V含量的TiAlVN膜均为面心立方结构,呈TiN(111)面择优取向。随V原子分数的增大,TiAlVN膜的硬度增大,抗高温氧化性能变差。当V原子分数为16.96%(即磁控溅射的V靶功率为60 W)时,TiAlVN膜的硬度最高(为31.67 GPa),抗高温氧化性能较好。展开更多
Differences in wear rate, morphology of the worn surface and debris, and the microstructure in subsurface of the Ti 6Al 4V alloy after wear in air and vacuum were compared. The wear rate of Ti 6Al 4V alloy in air is h...Differences in wear rate, morphology of the worn surface and debris, and the microstructure in subsurface of the Ti 6Al 4V alloy after wear in air and vacuum were compared. The wear rate of Ti 6Al 4V alloy in air is higher than that in vacuum in all the ranges of sliding velocities and applied loads. The wear of Ti 6Al 4V alloy in air is controlled by a combination of abrasion, oxidation and delamination with micro cracks remaining in subsurface. Under the vacuum condition, the surface layer of Ti 6Al 4V alloy experiences a severe plastic deformation on a great scale, which results in an ultra fine microstructure.展开更多
JOHNSON-COOK(J-C) model was used to calculate flow shear stress—shear strain curve for Ti-6Al-4V in dynamic torsion test. The predicted curve was compared with experimental result. Gradient-dependent plasticity(GDP) ...JOHNSON-COOK(J-C) model was used to calculate flow shear stress—shear strain curve for Ti-6Al-4V in dynamic torsion test. The predicted curve was compared with experimental result. Gradient-dependent plasticity(GDP) was introduced into J-C model and GDP was involved in the measured flow shear stress—shear strain curve, respectively, to calculate the distribution of local total shear deformation(LTSD) in adiabatic shear band(ASB). The predicted LTSDs at different flow shear stresses were compared with experimental measurements. J-C model can well predict the flow shear stress—shear strain curve in strain-hardening stage and in strain-softening stage where flow shear stress slowly decreases. Beyond the occurrence of ASB, with a decrease of flow shear stress, the increase of local plastic shear deformation in ASB is faster than the decrease of elastic shear deformation, leading to more and more apparent shear localization. According to the measured flow shear stress—shear strain curve and GDP, the calculated LTSDs in ASB are lower than experimental results. At earlier stage of ASB, though J-C model overestimates the flow shear stress at the same shear strain, the model can reasonably assess the LTSDs in ASB. According to the measured flow shear stress—shear strain curve and GDP, the calculated local plastic shear strains in ASB agree with experimental results except for the vicinity of shear fracture surface. In the strain-softening stage where flow shear stress sharply decreases, J-C model cannot be used. When flow shear stress decreases to a certain value, shear fracture takes place so that GDP cannot be used.展开更多
The properties and forming process of prealloyed powder metallurgy(PM) Ti-6Al-4V alloy were researched for application of high performance of titanium parts. Hot isostatic press(HIP) technology and two kinds of powder...The properties and forming process of prealloyed powder metallurgy(PM) Ti-6Al-4V alloy were researched for application of high performance of titanium parts. Hot isostatic press(HIP) technology and two kinds of powders were used in the prealloyed processing to get full density material. Tensile properties,impact toughness and fracture toughness of PM Ti-6Al-4V alloy were studied and discussed. The microstructures were examined with optical microscope and the morphologies of powders were observed by SEM. Forming processes were performed to fabricate PM titanium parts. The experiment results show that the prealloyed PM Ti-6Al-4V alloy has same good properties as wrought material and the complex shape PM parts can be near-net-shaped. Some of the parts have been commercially used. This indicates that the prealloyed process should have bright prospects in making high-performance,complex shape and low-cost titanium alloy parts.展开更多
文摘采用磁控溅射法在不同V靶功率下制得一系列不同V含量的TiAlVN膜。通过能谱分析、X射线衍射、硬度测量和高温退火研究了V原子分数对Ti Al VN膜成分、晶相结构、硬度和抗高温氧化性能的影响。结果表明,不同V含量的TiAlVN膜均为面心立方结构,呈TiN(111)面择优取向。随V原子分数的增大,TiAlVN膜的硬度增大,抗高温氧化性能变差。当V原子分数为16.96%(即磁控溅射的V靶功率为60 W)时,TiAlVN膜的硬度最高(为31.67 GPa),抗高温氧化性能较好。
文摘Differences in wear rate, morphology of the worn surface and debris, and the microstructure in subsurface of the Ti 6Al 4V alloy after wear in air and vacuum were compared. The wear rate of Ti 6Al 4V alloy in air is higher than that in vacuum in all the ranges of sliding velocities and applied loads. The wear of Ti 6Al 4V alloy in air is controlled by a combination of abrasion, oxidation and delamination with micro cracks remaining in subsurface. Under the vacuum condition, the surface layer of Ti 6Al 4V alloy experiences a severe plastic deformation on a great scale, which results in an ultra fine microstructure.
基金Project(2004F052) supported by the Educational Department of Liaoning Province, China
文摘JOHNSON-COOK(J-C) model was used to calculate flow shear stress—shear strain curve for Ti-6Al-4V in dynamic torsion test. The predicted curve was compared with experimental result. Gradient-dependent plasticity(GDP) was introduced into J-C model and GDP was involved in the measured flow shear stress—shear strain curve, respectively, to calculate the distribution of local total shear deformation(LTSD) in adiabatic shear band(ASB). The predicted LTSDs at different flow shear stresses were compared with experimental measurements. J-C model can well predict the flow shear stress—shear strain curve in strain-hardening stage and in strain-softening stage where flow shear stress slowly decreases. Beyond the occurrence of ASB, with a decrease of flow shear stress, the increase of local plastic shear deformation in ASB is faster than the decrease of elastic shear deformation, leading to more and more apparent shear localization. According to the measured flow shear stress—shear strain curve and GDP, the calculated LTSDs in ASB are lower than experimental results. At earlier stage of ASB, though J-C model overestimates the flow shear stress at the same shear strain, the model can reasonably assess the LTSDs in ASB. According to the measured flow shear stress—shear strain curve and GDP, the calculated local plastic shear strains in ASB agree with experimental results except for the vicinity of shear fracture surface. In the strain-softening stage where flow shear stress sharply decreases, J-C model cannot be used. When flow shear stress decreases to a certain value, shear fracture takes place so that GDP cannot be used.
文摘The properties and forming process of prealloyed powder metallurgy(PM) Ti-6Al-4V alloy were researched for application of high performance of titanium parts. Hot isostatic press(HIP) technology and two kinds of powders were used in the prealloyed processing to get full density material. Tensile properties,impact toughness and fracture toughness of PM Ti-6Al-4V alloy were studied and discussed. The microstructures were examined with optical microscope and the morphologies of powders were observed by SEM. Forming processes were performed to fabricate PM titanium parts. The experiment results show that the prealloyed PM Ti-6Al-4V alloy has same good properties as wrought material and the complex shape PM parts can be near-net-shaped. Some of the parts have been commercially used. This indicates that the prealloyed process should have bright prospects in making high-performance,complex shape and low-cost titanium alloy parts.
