Fe Content Optimization for Enhanced Wear Resistance of SiC3D/Cu–Fe Interpenetrating Phase Composites: A Multiscale Simulation and Experimental Study

A multiscale framework combining finite element analysis (FEM), molecular dynamics (MD) simulations, and pin–on–disc experiments was developed to optimize the Fe content of SiC3D/Cu–Fe interpenetrating phase composites (IPCs) and to reveal the load–bearing and wear mechanisms underlying their tribological performance. Because the wear resistance of IPCs is governed by the load–bearing capacity of the reinforcing skeleton through the Archard wear relation, the optimal matrix composition was predicted by compressive MD/FEM simulations rather than by directly simulating the multi–physics friction process. FEM showed that the three–dimensionally continuous SiC3D skeleton carries the dominant share of the normal load and transfers it to the matrix through the interface. MD screening over Fe contents of 5–20 at.% identified 5 at.% Fe as optimal, where the face–centered cubic phase fraction reaches its maximum and the compressive strength peaks; the Cu-5%Fe matrix was therefore selected for pressureless infiltration of a Cu film–sprayed SiC3D skeleton. The as–fabricated IPCs exhibited spontaneous oxygen segregation to the SiC/Cu interface, forming Si–O–Cu bridging bonds that strengthen interfacial bonding. Pin–on–disc tests under loads of 20–100 N showed a stable friction coefficient (0.45–0.54) and a low wear rate (0.93–3.01 × 10−12 m3·N−1·m−1) over the whole load range. The FEM–predicted wear depth deviated from the measured value by approximately 7.7%, and the friction tests confirmed the MD–predicted optimum, establishing a self–consistent simulation–to–experiment framework from macroscopic load bearing to atomic–scale matrix strengthening.