选区激光熔化Ti-6Al-4V合金在高应变速率下力学性能的有限元模拟

采用选区激光熔化(SLM)技术制备Ti-6Al-4V合金,经真空退火热处理和热等静压处理后,研究了合金准静态和高应变速率(500~3000s^-1)下的力学性能;对双线性材料模型进行标定,将所得到的材料参数应用于霍普金森压缩试验的有限元模拟中,并将模拟结果与试验结果进行对比。结果表明:经真空退火和热等静压处理后,SLM成形合金的组织为α相和β相,呈网篮组织形貌;与准静态条件下的相比,在高应变速率下SLM成形合金的断后伸长率得到明显提高;模拟得到的归一化真应力-真应变曲线与试验得到的相吻合,平均相对误差为2.5%,其材料参数可用于后续的瞬态冲击仿真分析中。

Finite Element Simulation of Mechanical Properties of Selective Laser Melted Ti-6Al-4V Alloy at High Strain Rates

Ti-6Al-4V alloy was prepared by selective laser melting(SLM)technique.After post vacuum annealing and hot isostatic pressing treatment,the mechanical properties of the alloy at quasi-static and high strain rates(500-3000 s^-1)were studied.The calibration of bi-linear material model was implemented;the obtained material parameters were applied to the finite element simulation of Hopkinson compression test,and the simulation results were compared with the test results.The results show that the microstructure of SLM formed alloy after vacuum annealing and hot isostatic pressing treatment was composed ofαphase and β phase with the net basket structure morphology.Compared with that under quasi-static condition,the percentage elongation after fracture of the SLM formed alloy at high strain rates was improved significantly.The normalized true stress-true strain curve obtained by simulation was consistent with test results,and the average relative error was 2.5%,indicating the material parameters was recommended for the subsequent transient impact simulation analysis.