Tailoring the enhanced mechanical behavior of 6061Al composites via nano SiCp and micron B4Cp addition

Abstract

In this work, the hybrid micron B4C particles (m-B4Cp) and nano SiC particles (n-SiCp) reinforced 6061Al matrix composites were prepared by powder metallurgy. The synergistic effects of hybrid m-B4Cp and n-SiCp were investigated. The results showed that m-B4Cp were well dispersed in the matrix, while n-SiCp were uniformly distributed inside the grains as well as at the grain boundaries. The coupled addition of n-SiCp and m-B4Cp significantly refined the grain size of matrix from 3.60 μm to 0.91 μm. The synchrotron X-ray computed tomography (SR-CT) revealed that the volume of pores increased with increase of particle content. Compared with the composites reinforced with only one type of particle, the 6061Al composites reinforced with micro and nano dual-size particles possessed higher tensile strength, while maintaining reasonable plasticity. The strengthening contributions to the yield strength improvement of 6010Al matrix composites reinforced with micro and nano dual-size particles are resulted from thermal expansion mismatch strengthening, fine grain strengthening and Orowan strengthening caused by n-SiCp.