Laser powder bed fusion of 17–4 PH stainless steel: A comparative study on the effect of heat treatment on the microstructure evolution and mechanical properties

17–4 PH (precipitation hardening) stainless steel is commonly used for the fabrication of complicated molds with conformal cooling channels using laser powder bed fusion process ( L -PBF). However, their microstructure in as-printed condition varies notably chemical composition feedstock powder, resulting different age-hardening behavior. In present investigation, components were fabricated by -PBF from two powders, and subsequently subjected to combinations post-process heat treatments. It was observed that conditions could be almost fully martensitic or ferritic, depending on ratio Cr eq /Ni powder. Aging treatment at 480 °C improved yield ultimate tensile strengths components. specimens structures exhibited accelerated response compared ferritic due higher lattice distortion dislocation accumulation, “dislocation pipe diffusion mechanism”. also found highly susceptible formation reverted austenite during direct aging treatment, where 19.5% phase appeared after 15 h aging. Higher fractions activates transformation induced plasticity improves ductility treated specimens. The results study can tailor printed treatments achieve a good combination mechanical properties.