effect of selective laser melting fabrication parameters and heat treatment on the microstructure and mechanical properties of maraging 300 alloy

Selective laser melting (slm) is a widely used additive manufacturing method for 3d-printing metal parts. this study investigates how slm parameters affect the density, microstructure, and mechanical properties of maraging steel 300. a process window was developed, revealing that maximum density and minimal porosity are achieved when laser energy density exceeds 50 j/mm³. optimal parameters—100 mm/s scan speed, 20 μm layer thickness, 0.15 mm hatch distance, stripe scanning strategy, and xz build direction—were identified. optimal processing reduced porosity, increased martensite content, and enhanced strength, reaching 1064 mpa and improving by 75% to 1862 mpa after aging and solution treatment. strength gains were attributed to the uniform dispersion of nano-sized precipitates (such as ni(mo)3 and ni(ti, al)3) within the martensitic matrix. additionally, it was found that higher cooling rates further improve the mechanical strength of heat-treated parts.