Microstructure and tensile properties of SiC nanoparticles reinforced magnesium matrix composite prepared by multidirectional forging under decreasing temperature conditions

Multidirectional forging (MDF) under decreasing temperature conditions was adopted to process SiC nanoparticles reinforced magnesium matrix composite. The results showed that grains of the nanocomposite were effectively refined while the amount of precipitated phases was significantly increased after MDF under decreasing temperature conditions. The precipitated phases as well as dispersed SiC nanoparticles could hinder the growth of dynamic recrystallization. The yield strength and ultimate tensile strength of the nanocomposites were increased compared with that of as-cast nanocomposite. This improvement could be attributed to obvious grain refinement as well as Orowan strengthening effect introduced by the dispersed SiC nanoparticles and the precipitated phases. Microcrack could initiate within the SiC nanoparticle dense zones during tensile test at room temperature, resulting in decrease of the elongation.