Effects of Quasi-Static Strain Rate and Temperature on the Microstructural Features of Post-Processed Microstructures of Laser Powder Bed Fusion Ti6Al4V Alloy

Abstract

This study documents an investigation of the flow stress properties and microstructuralfeatures of Ti6Al4V (ELI) alloy produced using laser powder bed fusion (LPBF). Selected heattreatment strategies were applied to the material to obtain different microstructures. The influence ofquasi-static strain rates and temperature on the obtained microstructures of this material and theirstrain hardening properties are documented in this study. All microstructures of the alloy formedin this study were found to be sensitive to quasi-static strain rates and temperatures, where theirflow stresses increased with increasing strain rate and decreased for tests conducted at elevatedtemperatures. The strain hardening rates of the fine microstructures were found to be high comparedto those of coarse microstructures. The strain hardening rates for the various forms of LPBF Ti6Al4V(ELI) examined here were found to diminish with increasing test temperature. Though the deformedsurfaces of the built samples were largely dominated by adiabatic shear bands (ASBs), the absence ofASBs was noted for all samples tested at a temperature of 500 ◦C and an imposed strain of 30%