Characterization of microstructure and texture evolution of selective laser melting of nickel-based alloy subjected to machining

Abstract

Machining is one of the most commonly used post-processing techniques to enhance surface quality and mechanical properties of components fabricated by selective laser melting (SLM). The inhomogeneous microstructure resulting from the SLM process has a significant impact on machining-induced material responses within the affected layer. Turning trials were performed on SLMed IN625 nickel-based alloy by varying cutting speeds. Their metallurgical responses beneath the machined surface were characterized in terms of grain morphology, crystallographic structure, and element distribution. Experimental results show that the white layer consists of an amorphous structure produced under high cutting speeds over 48 m/min. Also, turning has a slight impact on the initial 〈001〉 texture evolution, and oxidation reaction is absent from the machined surface while showing elements redistribution. The findings offer insights into the visual understanding of microstructure evolution toward additively manufactured nickel-based alloy specimens as well as cutting parameters optimization subjected to post-turning operation.