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.

Fabrication of Electron Beam Melted Titanium Aluminide: The Effects of Machining Parameters and Heat Treatment on Surface Roughness and Hardness

“…Compared to other additive manufacturing (AM) techniques, the fabrication process of Ti alloy-based parts is carried out at temperatures around 1000 • C. This temperature range minimizes or eliminates temperature gradients, thereby facilitating the production of stress-relaxed parts [22]. Similar to other additive manufacturing (AM) processes, such as selective laser melting (SLM) [23][24][25][26], electron beam melting (EBM) [27] is a powder-bed fusion technique used to directly manufacture complex-shaped geometries from a 3D CAD file; the other most popular metal additive manufacturing method is directed energy deposition (DED), where the metal powder is blown through a carrier gas and the transferred metal powder on the substrate is melted using a high energy source such as a laser beam [28][29][30]. During the entirety of the EBM fabrication process, which operates under a vacuum environment, the powder material is fed and fused by scanning a focused laser or electron beam as a heat source.…”