Martensitic steels via laser powder-based additive manufacturing: Recent advances in process parameters, microstructure tailoring, and mechanical performance

Ferrous alloys, as foundational structural materials, hold great promise for metal additive manufacturing (AM). Among them, martensitic steel (MS) has attracted attention in laser powder based-AM due to its high strength, excellent hardenability, and cost-effectiveness. Extensive efforts have focused on optimizing process parameters and tailoring microstructures to enhance mechanical performance. However, current studies reveal significant variability in mechanical properties, especially in as-built conditions, posing challenges to broader applications. This review summarizes recent advances in microstructural characterization, strengthening mechanisms, and mechanical evaluation of AM-fabricated MS, focusing on two key laser powder-based methods: laser powder bed fusion (LPBF) and laser directed energy deposition (LDED). Special emphasis is placed on three major subclasses—maraging steels, precipitation-hardening martensitic stainless steels, and carbon-containing martensitic steels—widely used in aerospace, automotive, and tooling industries for their desirable mechanical performance in demanding applications. The review also explores process–microstructure–property relationships under both as-built and heat-treated states. A critical assessment of existing work highlights the urgent need for more quantitative studies on microstructure–property correlations, to fully leverage AM’s unique solidification behavior and guide microstructural design for improved performance.