Investigating Microstructure and Properties of 316L Stainless Steel Produced by Wire-Fed Laser Metal Deposition

Abstract

Wire feedstock laser metal deposition (WFLMD) is a metal additive manufacturing (AM) technique that has several advantages over other AM processes, most notably lower feedstock costs, higher deposition rates, and the ability to make large continuous parts. The microstructure and properties of materials produced by this new technique must be studied for comparison to other techniques. This work briefly reviews published properties of 316L stainless steel produced by other processes and compares them to experimentally determined properties of 316L samples produced with WFLMD under reduced atmospheric conditions. Relative densities from WFLMD were greater than 98% and microstructure analysis showed primarily austenite, with some ferrite and carbide phases. Electron backscatter diffraction showed the presence of tilted or twisted grain structures. Strength and hardness were comparable to or better than those resulting from other processes. Fractography indicated ductile tearing with few defects, though some defects were identified with microscopy, which can be attributed to minor contamination.