Additive manufacturing and characterization of a stainless steel and a nickel alloy

Abstract

Recently, additive manufacturing is of interest, and there is a trend to study additively manufactured materials such as Inconel 718 and 316L stainless steel. Additive manufacturing brings the easiness of production of complex geometries, avoids expensive tools, helps achieve interesting microstructures and obtaining promising results for future applications. Since the additive procedure is sensitive to many fabrication variables thereby affecting the microstructure and mechanical properties. This motivation promotes investigating the additively manufactured microstructure of 316L stainless steel and Inconel 718. While 316L stainless steel was fabricated using an electron-based powder bed fusion manner, directed energy deposition was preferred for Inconel 718. Samples were examined utilizing optical and scanning electron microscopes. Results suggest processing of 316L stainless steel gives rise to the same porosity rate as Inconel 718. Bimodal equiaxed austenite grain morphology was observed whereas no dendrite presence was detected for 316L stainless steel. Additive manufacturing types do not cause a significant change in the level of porosity for Inconel 718 alloy. Unlike the case of stainless steel, additive manufacturing results in dendritic microstructure formation in Inconel 718 whereas powder bed fusion-type production triggers a better refinement compared to that of directed energy deposition.