Surface Texture and Microstructural Characterization of Thin-Walled Ti6Al4V Part Processed Using Laser Powder Bed Fusion Technique: Effect of Build Direction

Abstract

Objective: The current research investigates the surface texture and microstructural characterization of thin-walled Ti6Al4V along the build direction processed using laser powder bed fusion (LPBF) technology using an intra-comparison approach. Methodology: The two-dimensional and three-dimensional surface morphology and multi-scale surface roughness analysis of all Ti6Al4V samples were performed using an opto-digital microscope (with extended focus imaging coupled with high dynamic range imaging). Moreover, the scanning electron microscope, microhardness tester, and X-ray diffraction techniques were used to analyze the microstructural and microhardness values. Findings: (1) The lath thickness was relatively thicker in the LPBF-processed Ti6Al4V sample’s microstructure at central locations than in the top and bottom locations. (2) The areal surface roughness (Sa), Rk, and Sk values were relatively lower for the middle region than for the bottom and top regions of the thin-walled part, implying nonuniform surface topography along the build direction. (3) The middle region had a higher surface texture and texture amplitude symmetry periodicity than the top and bottom regions along the build direction. Value: Overall, the established methodology employed on the thin-walled Ti6Al4V part processed using LPBF technology enables the selection criteria of a suitable surface finishing process to achieve isotropic finish for practical industrial applications. Copyright © 2022 by ASTM International.