Simultaneously enhanced strength and ductility of Cu matrix composites by incorporating Al2O3 aerogel particles

The pursuit of developing high-performance Cu composites has always focused on maintaining high electrical conductivity, while simultaneously enhancing strength and ductility. However, it is well-known that ductility decreases as strength increases and vice versa. Overcoming this inherent limitation is a challenge in the development of high-performance Cu. To address this challenge, we propose an effective strategy of utilizing Al2O3 aerogel particles (Al2O3(A)(p)) as reinforcements to prepare high-performance Cu matrix composites via powder metallurgy. The results indicate that after ball milling dispersion and densification treatment, nanoscale Al2O3(A)(p) can be uniformly distributed in the matrix, partially achieving intragranular distribution and forming a semi-coherent bonding interface between Al2O3(A)(p) and Cu. The Cu-0.5 wt.% Al2O3(A)(p) has a high tensile strength of 470 MPa and elongation to failure up to 10% while maintaining a high electrical conductivity of 92%IACS. Owing to the increase in the work hardening rate, the strength and uniform elongation of the composite are concurrently improved. In addition, the mechanisms for high strength and ductility are discussed. This work provides a simple and feasible strategy, along with novel insights, for the design of metal matrix composites with both high strength and ductility.