Lee Woei-Shyan, Lin Chi-Feng, Chen Tao-Hsing, Hwang Hsin-Hwa
Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
J Mech Behav Biomed Mater. 2008 Oct;1(4):336-44. doi: 10.1016/j.jmbbm.2008.01.002. Epub 2008 Jan 19.
This study uses the compressive split-Hopkinson pressure bar to investigate the mechanical behaviour of Ti-15 Mo-5 Zr-3 Al alloy deformed at strain rates ranging from 8 x 10(2) to 8 x 10(3) s(-1) and temperatures between 298 and 1173 K. The results indicate that the mechanical behaviour of the alloy is highly sensitive to both the strain rate and the temperature. The flow stress curves are found to include a work hardening region and a work softening region. The strain rate sensitivity parameter, m, increases with increasing strain and strain rate, but decreases with increasing temperature. The activation energy varies inversely with the flow stress, and has a low value at high deformation strain rates or low temperatures. Correlating the mechanical properties of the Ti alloy with the transmission electron microscope (TEM) observations, it is concluded that the precipitation of alpha phase dominates the fracture strain. TEM observations reveal that the amount of alpha phase increases with increasing temperature below the beta transus temperature. The maximum amount of alpha phase is formed at a temperature of 973 K and results in the minimum fracture strain observed under the current loading conditions.
本研究采用压缩式分离霍普金森压杆，研究了Ti-15Mo-5Zr-3Al合金在应变率为8×10²至8×10³s⁻¹以及温度在298至1173K范围内变形时的力学行为。结果表明，该合金的力学行为对应变率和温度都高度敏感。发现流动应力曲线包括加工硬化区和加工软化区。应变率敏感参数m随应变和应变率的增加而增大，但随温度的升高而减小。激活能与流动应力成反比，在高变形应变率或低温下具有较低的值。将Ti合金的力学性能与透射电子显微镜（TEM）观察结果相关联后得出结论，α相的析出主导了断裂应变。TEM观察表明，在低于β转变温度时，α相的数量随温度升高而增加。α相的最大数量在973K的温度下形成，并导致在当前加载条件下观察到的最小断裂应变。
