Parameter Optimization and Flaw Type Dependent Tensile Properties of 15-5PH Stainless Steel Manufactured by Laser Powder Bed Fusion

Careful consideration of processing parameters to mitigate defect formation is crucial to ensure reliability of components produced by laser powder bed fusion (LPBF). In this work, additive manufacturing parameter optimization and flaw type dependent tensile properties of 15-5 precipitation hardened (PH) stainless steel produced by LPBF is examined to understand the correlation among processing parameters, flaw types, and corresponding tensile mechanical behavior. It is reported that LPBF samples with keyhole (KH) pores exhibit superior mechanical properties compared to those induced with lack-of-fusion (LOF) flaws, for a given relative density level. Diminished mechanical properties in samples with LOF flaws is correlated to the flaws' irregular shapes and sharp corners, causing stress concentration. Minimal improvements to the mechanical properties of LOF-induced samples, despite increasing relative density, indicate even small amounts of LOF flaws cause stress concentration and crack initiation. Conversely, KH pores exhibit high circularity and lower curvature values, and samples with KH pores demonstrate a strong correlation between tensile properties and relative density. Findings from this study suggest that when suboptimal LPBF processing is inevitable, favoring excessive energy input to induce KH pores over LOF flaws can lead to more predictable mechanical behavior of LPBF components. The parameter optimization and flaw type dependent tensile properties of 15-5PH stainless steel produced by laser powder bed fusion (LPBF) is examined to quantitatively understand the correlation among processing parameters, flaw types, that is, keyhole (KH) pores or lack-of-fusion (LOF) flaws, and corresponding tensile mechanical behavior. LPBF samples with KH pores exhibit superior mechanical properties compared to those with LOF flaws, given the same relative density.image (c) 2024 WILEY-VCH GmbH