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 (500-3 000 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 of α phase 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.