Engineering WC morphology and content enables improved mechanical properties in laser-cladded WC/iron-based composites

WC-reinforced iron-based metal matrix composites (MMCs) combine the superior hardness of WC with the intrinsic ductility of metallic matrices, which are ideal for remanufacturing worn engineering components. Nevertheless, ceramic particle agglomeration and internal defects limit the service life of repaired components. This study investigated the effects of WC morphology (19 μm spherical vs. 4 μm non-spherical) and content (5-20 wt.%) on defects, microstructure, and mechanical properties of laser-cladded WC/JG-11 composites, and successfully fabricates low-defect composites with superior wear resistance. Within the explored range, the composites with 10 wt.% WC (4 μm) exhibited optimal wear resistance and enhanced microhardness with the lowest defects. Due to weak dissolution of WC and large-scale flaking, the WC (19 μm) addition exhibited limited defect suppression and unstable wear resistance, despite adjusting its mass fraction over the tested range. In contrast, the addition of WC (4 μm) improved the laser energy absorption capacity of the molten pool, enhancing surface quality and reducing defects. Specifically, 10 wt.% WC (4 μm) reduced porosity by 92.3%, refined grains by 41.68%, and decreased friction coefficient and wear volume by 60.47% and 81.85% versus JG-11 alloy. However, 5 wt.% WC (4 μm) showed limited dissolution and M x C y precipitation, while 15-20 wt.% induced cracks and degraded wear resistance. The regulating mechanism of the WC morphology and content control relies on WC dissolution and M x C y precipitation, achieving second-phase strengthening and grain refinement. This work provides an effective approach for additive manufacturing and component remanufacturing with high-performance metal matrix composites.