Phase-Field Simulation of the Solidification Process of Particle-Reinforced Cu Matrix Composites

As a typical class of high-strength and high-conductivity materials, particle-reinforced copper matrix composites show great promise for application in critical conductive components. However, when such composites are prepared via melting methods, challenges such as the agglomeration of reinforcing particles and difficulty controlling their spatial distribution often arise, limiting the application of these composites in conductive parts. In this study, a phase-field method is employed with order parameters introduced to characterize the interaction between solid–liquid interfaces and reinforcing phases. By reconstructing the free-energy functional of the multi-phase-field model, the effects of undercooling and solid–liquid interface properties on particle–interface interactions are investigated. Simulations are conducted for solidification for different particle sizes and in different particle aggregation states, dynamically illustrating the evolution behavior of nanoparticles at the solid–liquid interface. The results indicate that particle migration velocity and distance rise with increased particle mobility due to reduced melt flow resistance. Higher undercooling accelerates solidification front propagation but curtails particle pushing distance, while the interface gradient coefficient (ε2) only inhibits particle migration distance with negligible influence on peak migration velocity. In single-crystal matrices, agglomerate morphology, orientation angle, and aggregation degree jointly affect migration behavior: irregular agglomerates undergo obvious morphological deformation, and migration distance increases when the orientation angle ranges from 0° to 90° and decreases with higher aggregation degrees. Fine particles are repelled to grain boundaries for agglomeration, whereas large particles are engulfed inside grains. Powders were fabricated via gas atomization, and the results of scanning electron microscopy characterization experiments confirm the simulation reliability. The results provide valuable insights for the controlled distribution of nanoparticles within composite materials.