Effect of nanoparticle content on the microstructural and mechanical properties of nano-SiC dispersed bulk ultrafine-grained Cu matrix composites

In this study, the microstructural and mechanical features of monolithic pure Cu and Cu matrix nanocomposites reinforced with three different fractions (2, 4, and 6 vol%) of SiC nanoparticles (n-SiC) fabricated via a combination of high energy mechanical milling and hot pressing techniques were investigated. The fabricated composites exhibited homogeneous distribution of the n-SiC with few porosities. It was found that the grain refinement, the planar features within the grains, and the lattice strains increase with increase in the n-SiC content. The yield and compressive strengths of the nanocomposites were significantly improved with increases in the n-SiC content up to 4 vol%; then they decreased due to the weak interface strength at higher amounts of n-SiC content. This improvement was attributed to the grain refinement strengthening and homogeneous distribution of the n-SiC. Furthermore, studies on different strengthening mechanisms showed that Hall-Petch strengthening mechanism is the most important factor. The yield strength was calculated theoretically using common analytical models. Clyne approach showed good agreement with experimental data and were more accurate than the other methods developed for predicting the strength of metal matrix nanocomposites. (C) 2013 Elsevier Ltd. All rights reserved.