In this work, TiC/M2 high speed steel metal matrix composites (MMCs) were prepared using the ball milling method and laser powder bed fusing process. By controlling the TiC content in TiC/M2HSS, the grain size, phase composition, and frictional wear properties of the samples were enhanced. The results showed that when TiC/M2HSS was supplemented with 1% TiC, the surface microhardness of the samples increased to a maximum value and the wear volume decreased by approximately 39%, compared to pure M2HSS. The hardness and friction wear properties of the TiC/M2HSS composites showed a decreasing trend as the TiC content increased, owing to an increase in internal defects in the samples, as a result of excess TiC addition. The physical phases of the TiC/M2HSS MMC samples prepared by LPBF were dominated by the BCC phase, with some residual FCC phases and carbide phases. This work explored the possibility of enhancing the frictional wear performance of TiC/M2HSS samples by controlling the TiC content.

22MnCrNiMo steel, a high-strength low-alloy material, is primarily used in the production of mooring chains for offshore oil platforms, offshore wind turbines, and ships. The application of additive manufacturing technology allows for the direct fabrication of seamless mooring chains. This paper investigates the selective laser melting (SLM) process parameters for 22MnCrNiMo mooring chain steel, analyzing the effects of different process parameters on the microstructure, phase composition, and mechanical properties of the steel. The experimental results demonstrate that under the laser parameters of 200 W laser power, 800 mm/s scanning speed, 30 μm layer thickness, and 110 μm scanning spacing, the SLM-formed parts exhibit the best comprehensive mechanical properties, with a microhardness of 513.2 HV0.5, a tensile strength of 1223 MPa, a yield strength of 1114 MPa, an elongation of 8.5%, and an impact energy of 127 J. This study reveals the microstructure evolution and the mechanism of enhanced mechanical properties in SLM-fabricated 22MnCrNiMo steel, providing a new approach for the preparation of high-performance mooring chains using 22MnCrNiMo steel.

Insufficient ductility and processing-dependent mechanical properties limit laser powder bed-fused (LPBF) high-nitrogen stainless steels. This study investigated short-term solution treatment of an Fe–Cr–Mn–Mo–N duplex stainless steel using two as-built samples with distinct microstructures and elongations. Samples were treated at 1050 and 1100 °C for 10 min and water quenched. Microstructure and deformation behavior were characterized by electron backscatter diffraction, tensile testing, loading–unloading–reloading experiments, and transmission electron microscopy. Treatment increased the austenite fraction from 16.0 and 21.1% to 70.8–77.0%, producing an austenite-dominated duplex microstructure with residual ferrite as short strips or isolated islands. Differences in tensile properties between the initial states decreased substantially, with ultimate tensile strengths of 1030.9–1049.9 MPa and elongations of 29.45–33.82%. A representative sample treated at 1100 °C achieved 1030.9 MPa and 33.82% elongation. Its back stress showed an overall increase during plastic deformation, indicating a contribution of long-range internal stresses to strain hardening. Early deformation involved planar slip and localized stacking faults in austenite. Further deformation produced denser planar defects and local 9R structures in austenite, with pronounced dislocation tangles in ferrite. Short-term solution treatment thus enhanced ductility while retaining approximately 1 GPa strength and reducing property discrepancies between initial LPBF-built states.