Ta-TaC/Fe bundle-reinforced gradient composites with enhanced wear resistance via in-situ synthesis

A novel Ta-TaC/Fe bundle-reinforced composite was fabricated via lost foam casting and in-situ reaction to resolve the strength-toughness trade-off. The in-situ TaC growth exhibited parabolic diffusion-controlled kinetics, forming a bio-inspired “hard shell–tough core” architecture. The dense TaC layer (∼2014 HV0.05) is nearly five times harder than the gray cast iron (GCI) matrix. Tribological evaluations demonstrated that the composite reduced specific wear rates by ∼80% (10 N) and ∼45.9% (20 N) compared to unreinforced GCI. This improvement stems from a mechanism transition from severe adhesive spalling to mild three-body abrasion, as the protruding TaC skeleton effectively shields the matrix, validating the bundle configuration for high-performance castings.