Fabrication of Multiscale-Alumina Particles Reinforced Copper Matrix Composites with High-Energy Ball Milling and Hot Pressing

Cu-Al2O3 composite materials combining the good electrical of copper matrix and the high hardness of Al2O3 ceramic particles show great performance in electronics, electrical sliding contacts fields. However, the relationship of a dilemma between strength and ductility has become a limitation for the development of copper matrix composites. The previous works indicated that fine grain powders can improve interfacial bonding between the copper matrix and Al2O3 particles to further enhance strength while maintaining ductility. In the present work, the multiscale-alumina particles reinforced copper matrix composites were successfully fabricated by mixing high-energy ball milling and consolidation of hot-press sintering. SEM and TEM were used to observe the powder morphology and microstructure of Cu-Al2O3 composites. The results show that the reinforcing phase Al2O3 particles are uniformly dispersed in the copper matrix, which improves interfacial bonding between the copper matrix and Al2O3 particles. Especially, the micro Al2O3 particles play an important role in achieving an excellent tradeoff of strength and ductility in the Cu-Al2O3 composite. In addition, the microhardness of Cu-Al2O3 composites can be greatly improved by using the high-energy ball milling and hot-press sintering process. The research idea of this paper can provide a reference for other composite materials that need to improve mechanical properties.