激光选区熔化Ti-6Al-4V合金的动态力学性能及其本构关系

为了开展激光选区熔化（SLM）增材制造钛合金的动态力学性能研究，分别采用热模拟材料试验机、分离式霍普金森压杆装置对激光选区熔化钛合金在不同温度下进行了准静态和动态压缩实验，并基于实验结果拟合Johnson-Cook本构模型，同时对钛合金在高温、高应变率下的力学行为进行了有限元模拟。结果表明，相对于铸造或锻造钛合金，激光选区熔化钛合金具有更细小、均匀的组织，使其屈服强度有明显的提升，且表现出明显的应变率强化效应和热软化效应。有限元模拟结果与实验有着较高的重合度，进一步验证了本构参数的有效性，为扩大激光选区熔化技术及其产品的应用提供了理论基础。

Dynamic mechanical properties and constitutive relationship of selective laser melted Ti-6Al-4V alloy

Aiming at understanding the dynamic mechanical properties of titanium alloys additively manufactured by selective laser melting (SLM), quasi-static and dynamic impact experiments were carried out on selective laser melted Ti-6Al-4V alloy at different temperatures using thermal simulation material testing machine and SHPB device, respectively. Based on the experimental results, the parameters of Johnson-Cook constitutive model are fitted. Meanwhile, the mechanical behaviors of titanium alloy at high temperature and high strain rates were simulated by finite element method. The results show that the yield strength of selective laser melted Ti-6Al-4V alloy is enhanced significantly compared with those of wrought or forged counterparts, Moreover, it exhibits significant strain rate strengthening effect and thermal softening effect. The finite element simulation results are close to the experimental results and further validate the constitutive model parameters, which could provide a theoretical basis for expanding the application of selective laser melting technique and its products.