TC6钛合金力学行为及其失效研究

采用高温、高应变率耦合分离式Hopkinson Bar系统和100 KN微机控制电子万能试验机系统,对等轴晶粒组织的TC6钛合金圆柱形及帽形试样进行了力学试验,研究了其力学行为及其失效机理.结果表明:等轴晶粒组织TC6钛合金在准静态下变形时呈现应变强化效应,而在高应变速率下变形时,热软化与应变强化共存,流变应力呈现振荡,且表现出较强的应变率效应;TC6钛合金的动态变形表现为局域化变形,且在局域化变形区域出现裂纹,裂纹在此区域扩展贯穿整个试样,最终导致失效,而准静态下材料的变形表现为均匀化变形,当应变达到0.4时,材料沿最大剪切应力方向断裂失效.

Research on mechanical behavior and failure of TC6 titanium alloy

Using the technology of high temperature-high strain rate coupling split Hopkinson bar and universal testing machine controlled by computer of 100KN,the mechanical experiment under the condition of high strain-rate loading on cylindrical sample and hat-shape sample of TC6 titanium alloy with equiaxed structure have been conducted and its mechanical behavior and fracture failure have been investigated.It is showed that the TC6 titanium alloy with equiaxed structure take on the effect of strain-strengthening at quasi-static deformation while at high strain rate deformation,it show the strong effect of strain rate and its flow stress take on vibration due to coexistence of thermal softening and strain-strengthening.The dynamic deformation of TC6 titanium alloy takes the form of localized deformation and the crack often appear in this area.When the crack expands and run through the sample along the localized area,the material tested lose efficacy.The deformation of material is homogeneous at quasi-static deformation,and when the strain reaches to 0.4 approximately,fracture failure of the testing material occurs along direction of the maximum shear stress.