Enhanced microstructure homogeneity and mechanical properties of AZ91–SiC nanocomposites by cyclic closed-die forging

Abstract

The microstructure and mechanical properties of AZ91–SiC nanocomposites processed by cyclic closed-die forging were investigated. The results showed that much finer grain size and more homogeneous distribution of Mg17Al12 phase and SiC nanoparticles were obtained along with significant improvement in strength and elongation after five passes. During cyclic closed-die forging processing, the agglomeration of nanoparticles disintegrated through kneading effect induced by intense matrix flow, and the nano-sized SiC particles were dispersed uniformly into the matrix. However, a few SiC clusters still existed due to the high surface energy of nanoparticles. Properties enhancement of the composites was mainly attributed to Hall–Petch effect and Orowan strengthening.