Abstract:High temperature compressive tests of AZ91 Mg alloy were carried out at 573 723 K and strain rates of 0.001 1 s^-1. The microstructures of as-compressed samples were observed by optical microscopy and transmission electron microscopy (TEM), and the microhardness was also tested. It is shown that with the increase of temperature or the decrease of strain rate, the flow stress decreases, at the same time the dynamic recrystallization (DRX) of the alloy is more noticeable. The microstructures reveal that continuous dynamic recrystallization, which develops through conversion of low-angle grain boundaries into high-angle boundaries, occurs preferentially at the grain boundary.

Key words: AZ91 magnesium alloy; high temperature compression; continuous dynamic recrystallization