مشخصات پژوهش

Selective laser melting (SLM) facilitates the production of Co–Cr–Mo–W alloys with intricate geometries. However, the rapid solidification characteristic of the method results in microstructural heterogeneity that limits its mechanical and tribological reliability. This study systematically examines the impact of various postprocessing heat treatments on phase evolution, carbide precipitation, and the performance of an SLM fabricated Co–Cr–Mo–W alloy. Solution treatment, single-stage aging, double-stage aging, and direct aging were utilized to alter solute redistribution and precipitate morphology. The as fabricated alloy, distinguished by a refined cellular microstructure with elements segregation displayed a strength of 1228 MPa with a ductility of 17.5 % and poor wear resistance. Heat treatment modified the equilibrium between γ and ε phases and facilitated the development of M6C and M23C6 carbides, resulting in significant alterations in microstructure and wear performance. The direct aging at 980 ◦C resulted in a dense array of fine, well anchored precipitates that displayed a hardness of 557 HV and tensile strength of 1424 ± 28.48 MPa, while preserving acceptable ductility (7.9 ± 0.15 %), and concurrently achieved the lowest coefficient of friction of about 0.17. Conversely, multistage aging improved chemical homogeneity but produced relatively coarser precipitates, diminishing strengthening efficacy and facilitating particle pull out during wear. The findings establish a distinct structureproperty correlation, indicating that heat treatment provides a streamlined and efficient method to enhance the mechanical integrity and surface durability of SLM Co–Cr–Mo–W alloys for diverse applications.