Effect of solution treatment on microstructure and mechanical properties of laser-cladded Stellite 6 coatings on 2507 duplex stainless steel

To enhance the comprehensive performance of Stellite 6 coatings fabricated by laser cladding on 2507 duplex stainless steel substrates, this study optimized the synergistic solution treatment process (1150 degrees C holding for 60 min followed by water quenching) through JMatPro thermodynamic simulations. The coatings were prepared using laser cladding technology, with systematic characterization of solution treatment effects on phase composition, microstructure, and mechanical properties via XRD, SEM, EDS, microhardness, and tensile testing. Results demonstrate that the laser-cladded coating primarily consists of gamma-Co and CoCx phases. After solution treatment, homogeneous precipitation of M23C6 carbides was achieved with significant grain refinement (from 5.3-13.4 mu m to 5.3-6.1 mu m) and improved elemental distribution uniformity. The solution-treated coating exhibited enhanced microhardness from 456 HV to 495 HV (8.5 % improvement) and elevated tensile strength from 834 MPa to 895.8 MPa (7.5 % improvement) while maintaining 10.6 % elongation. Mechanistic analysis reveals that the synergistic effects of grain refinement and M23C6 dispersion strengthening effectively inhibit dislocation slip. The optimized heat treatment temperature simultaneously prevents detrimental phase precipitation (delta-phase and M2(C, N) in substrate). This method provides valuable guidance for fabricating highperformance Stellite 6 laser-cladded coatings.