Hot deformation behavior of Al18B4O33w/ZK60 magnesium matrix composite

The hot deformation behavior of ZK60 magnesium alloy reinforced with 20 vol.% of Al18B4O33 whisker was investigated by compression testing in temperature range of 523-723 K and strain rate range of 0.001-10 s-1. The deformation behavior was mainly dependent on strain rate and temperature on certain strain condition. Variations of flow behavior with deformation temperature as well as strain rate were analyzed. The microstructural evolution at different temperatures and strain rates are mainly characterized by twinning, dislocation slip and dynamic recrystallization (DRX) during the hot compression. They were observed by transmission electronic microscope (TEM). It is shown that twinning occurred at lower temperature and earlier deformation stage. Twinning is the main reason for the high strain hardening rate at relatively low temperature. The material showed DRX at higher temperature and moderate strain rate, which is the reason for flow softening at relatively high temperature. Al18B4O33 whiskers promote nucleation of DRX. A fine dislocation substructure forms upon hot deformation, leading to subgrain formation