Microstructure and properties of Al/cBN composites prepared by gas pressure infiltration

Aluminum matrix composites reinforced with cubic boron nitride particles (Al/cBN composites) were successfully fabricated via a gas pressure infiltration method. The effect of holding time (10–50 min) during the infiltration process on the interfacial microstructure, thermophysical properties, and mechanical performance was systematically investigated. For the 10 min holding time sample, the composite exhibits a peak thermal conductivity of 313 W/(m·K), which is approximately 32% higher than the theoretical thermal conductivity of pure Al (237 W/(m·K)). In contrast, the 30 min holding time sample achieves a low coefficient of thermal expansion (CTE) of 8.1 × 10 -6 /K and a high bending strength of 358 MPa, representing a balanced combination of superior thermophysical and mechanical properties. The reduced CTE and enhanced bending strength are attributed to strong interface bonding by interfacial reaction between cBN particles and the Al matrix. This work clarifies the relationship between holding time, interfacial structure, and properties of Al/cBN composites, providing a facile and effective strategy for tailoring interfacial bonding to achieve high-performance thermal management materials for high-power electronic packaging applications.