Synergistic strengthening mechanism of copper matrix composite reinforced with nano-Al2O3particles and micro-SiC whiskers

Abstract

Although Cu-Al2O3 composites have good comprehensive performance, higher mechanical properties and arc erosion resistance are still required to meet heavy-duty applications such as electromagnetic railguns. In this work, a novel hybrid SiCw/Cu-Al2O3 composite was successfully prepared by combining powder metallurgy and internal oxidation. The microstructure and mechanical behavior of the SiCw/Cu-Al2O3 composite were studied. The results show that nano-Al2O3 particles and micro-SiCw are introduced into the copper matrix simultaneously. Well-bonded interfaces between copper matrix and Al2O3 particles or SiCw are obtained with improved mechanical and arc erosion resistance of SiCw/Cu-Al2O3 composite. The ultimate tensile strength of the SiCw/Cu-Al2O3 composite is 508.9 MPa, which is 7.9 and 56.1% higher than that of the Cu-Al2O3 composite and SiCw/Cu composite, respectively. The strengthening mechanism calculation shows that Orowan strengthening is the main strengthening mechanism of the SiCw/Cu-Al2O3 composite. Compared with Cu-Al2O3 composite, the hybrid SiCw/Cu-Al2O3 composite has lower arc time and energy and better arc stability.