Tribological effects of varying volumetric energy density in additive manufacturing of inconel 718

Abstract

This study investigates the novel effects of varying volumetric energy density (VED) ratios on the tribological characteristics of Inconel 718 alloy fabricated using Laser Powder Bed Fusion (LPBF) process. Nine VED ratios were investigated, and samples underwent non-contact surface roughness tests, Vickers microhardness tests, and residual stress analysis. Notably, this study identified specific VED conditions where superior wear resistance was achieved, contributing new insights into optimizing LPBF parameters for tribological performance. Based on preliminary analysis, samples 1, 3, and 8 were selected for ball-on-disc wear testing. Sample 8, fabricated with 330 W laser power, 50 mm/s scan speed, 0.10 mm hatch spacing, and 0.05 mm layer thickness, demonstrated superior tribological behaviour with a 32.12% and 52.11% lower friction coefficient and 31% and 29.92% less mass loss compared to samples 1 and 3, respectively. The presence of γ-Ni, γ’-Ni3 (Al, Ti), γ-FCC, and γ’-L12 phases, along with microstructural features such as columnar and cellular dendritic structures, were confirmed via SEM and X-ray diffraction analyses. This study’s novel findings contribute valuable knowledge for optimizing Inconel 718 production via LPBF, particularly in enhancing wear resistance through tailored VED settings.