Microstructure, Mechanical Behavior, and Thermal Conductivity of Three-Dimensionally Interconnected Hexagonal Boron Nitride-Reinforced Cu-Ni Composite

A powder metallurgy-based strategy to in situ construct a three-dimensionally interconnected hexagonal boron nitride (3Di-hBN) layers surrounding the grains of Cu-Ni matrix through metal–organic chemical vapor deposition process was utilized to fabricate 3Di-hBN-reinforced Cu0.7-Ni0.3 (3Di hBN-Cu-Ni) composite. The effect of 3Di-hBN on the mechanical properties of 3Di hBN-Cu-Ni composite was assessed by comparing with pure Cu-Ni alloy (without hBN) fabricated via powder metallurgy route under similar processing conditions. Uniaxial tensile investigations showed that 3Di-hBN positively influenced the mechanical properties of 3Di hBN-Cu-Ni composite;  ∼16.3, ∼11.67, and ∼27.9% higher yield strength, UTS, and fracture toughness, respectively, compared to PM Cu-Ni alloy. The overall improved performance of 3Di hBN-Cu-Ni composite was attributed to the formation of 3Di-hBN layers at the interfaces of Cu-Ni grains, which enable the composite to withstand the applied load through the mechanisms of load transfer, dislocation strengthening, and grain refinement. In addition, thermal conductivity of 3Di hBN-Cu-Ni composite was found ∼10% higher than that of pure Cu-Ni alloy.