Development and characterization of a novel maraging steel fabricated by laser additive manufacturing

This study focuses on the development and characterization of a novel high Mo-element maraging steel fabricated using laser additive manufacturing. The maraging steel was subjected to direct aging treatment at 530 °C for 2 h to initiate the precipitation strengthening effect. We investigated the microstructure, nanoindentation characteristics, and mechanical properties of the maraging steel both before and after the aging treatment. The analysis revealed that the phase compositions of the maraging steel remained consistent before and after aging treatment, with both exhibiting a martensitic structure. However, the aging treatment facilitated the reverse transformation of austenite and promoted the precipitation of Fe2Mo particles and nanoscale spherical precipitation phases. The maraging steel treated through direct aging exhibited exceptional mechanical properties, demonstrating a nano-hardness ranging from 7.10 ± 0.17 GPa to 10.07 ± 0.13 GPa, along with a tensile strength of 1978 ± 38 MPa and an elongation of 7.36 %. Remarkably, these mechanical properties were found to be comparable to those of the aging-treated 18Ni300 maraging steel, underscoring the high performance achieved. The primary strengthening mechanism responsible for these excellent mechanical properties is attributed to the precipitation strengthening effect induced by Fe2Mo and nanoscale spherical precipitated phases. In conclusion, the combination of laser additive manufacturing and direct aging treatment presents a promising approach to fabricate high-performance maraging steels with outstanding mechanical properties. The findings from this research contribute to a deeper understanding of the microstructural evolution and strengthening mechanisms in high Mo-element maraging steels, offering significant implications for various applications in advanced engineering and manufacturing industries.