Laser metal deposition of 17-4 PH stainless steel: Geometrical, microstructural, and mechanical properties investigation for structural applications

Progress in Additive Manufacturing (AM) makes it a suitable technology for manufacturing parts exposed to extreme loading and environmental conditions. For widespread adoption, it is necessary to understand how the processing conditions affect the properties of the AM parts. The current work investigates the geo-metrical, mechanical and metallurgical properties of laser deposited 17-4 PH stainless steel powder. The energy density (ED) and Powder Deposition Density (PDD) influence the geometrical properties. Martensite and delta-ferrite morphologies dominate the as-built microstructure. The heat-treated microstructure was martensitic, with a minimal fraction of retained austenite. The average as-built Vickers hardness ranges from 327.7 HV to 402.3 HV. Impact energy for the as-built horizontal Charpy coupon was 21.1 J. As-built horizontal tensile test reveals yield strength of (937.61 MPa), UTS of (1008.06 MPa) and % elongation of (8.00). The mechanical properties improved depending on the heat treatment conditions. Horizontal tensile coupons subjected to high-pressure heat treatment and ageing reveal an average yield strength of (1391.72 +/- 174.08 MPa), an average UTS of (1504.07 +/- 140.86 MPa) and an average % elongation of (8.14 +/- 0.02). The processing conditions influenced the geometrical properties, whereas heat treatment conditions affect the final metallurgical and mechanical properties.(c) 2022 CIRP.