Effects of Electropulsing on the Microstructure and Microhardness of a Selective Laser Melted Ti6Al4V Alloy

Optimizing the microstructure and mechanical properties of the selective laser melted (SLM) Ti6Al4V alloy is an important issue both in the scientific and engineering interests. In this study, the rapid hardening and softening of the SLM-Ti6Al4V alloy is realized due to the obvious evolution of microstructures during the electropulsing treatment (EPT) with different discharge voltages. The microhardness of the EPT-7.5 kV sample decreased about 7% while the EPT-8 kV sample increased about 10% compared with the as-received sample. Scanning electron microscopy (SEM), electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) analysis were used to characterize the evolutions of alpha and beta grains and dis-location structures which are corresponding with the microhardness changes induced by EPT. Analysis shows that EPT could reduce the thermodynamic barrier for alpha -> beta solid-state phase transformation, further arise microstructure refinement in the SLM-Ti6Al4V alloy. This research shed some new light on rapidly and efficiently improving the microstructure and mechanical properties of the additive manufactured metal components. (c) 2021 Elsevier B.V. All rights reserved.