Effect of layer thickness on spatters oxidation of Hastelloy X alloy during powder bed fusion-laser beam processing

Abstract

This study investigates the impact of powder layer thickness on spatter generation and oxidation behavior during the processing of Hastelloy X. In-situ monitoring using optical tomography reveals that thicker powder layers result in a higher number of hot spatters generated during laser-melt-powder interaction. Scanning electron microscopy and Auger electron spectroscopy analysis demonstrate the presence of different types of spatters that oxidize differently depending on their origin. X-ray photoelectron spectroscopy analysis further shows that the surface enrichment of oxide-forming elements such as Al, Ti, Cr, and Fe varies with the type of spatter particle. Additionally, depth profile analysis using X-ray photoelectron spectroscopy indicates that the average oxide layer thickness increases from ∼2.5 nm in virgin to ∼68 nm in spatters generated at 150 μm powder layer thickness. The findings suggest that powder layer thickness is a crucial factor in controlling spatter generation and oxidation behavior during powder bed fusion-laser beam processing.