Dissimilar Maraging Stainless Steel With Superior Strength Matching Produced by Laser Repair and Tailored Heat Treatment

Laser repair of maraging steel components using dissimilar materials offers a promising route for performance restoration, but achieving compatible strength between the repair layer and substrate remains challenging. This study investigates laser melting deposition (LMD) of 17-4PH stainless steel onto a 00Cr12Ni10MoTi (S03) substrate followed by solution treatments at 750, 900, and 1050 °C and aging at 490 °C. The solution temperature governs precipitate dissolution and recrystallization in the 17-4PH layer and the microstructural stability of the S03 substrate, thereby determining strength matching and deformation compatibility. Insufficient solution treatment at 750 °C limits the strengthening response of the repair layer, whereas excessive solution treatment at 1050 °C induces pronounced grain coarsening in the S03 substrate. Among the investigated conditions, the 900 °C solution treatment provides the best overall balance between repair-layer strengthening and substrate stability. Under the SA900 condition, nanoscale Cu-rich precipitates effectively strengthen the 17-4PH repair layer, while the S03 substrate retains adequate ductility and deformation compatibility. Consequently, tensile specimens fractured preferentially within the substrate rather than at the interface, demonstrating reliable strength overmatching and sound interfacial bonding. This work establishes a viable heat treatment strategy for achieving interfacial mechanical compatibility in dissimilar martensitic steel repairs via LMD.