Aging microstructure and mechanical properties of ZA84+Ca-Bi magnesium alloy

As-cast microstructure and its properties, aging hardening effect and phase transformation during aging of ZA84+Bi-Ca alloy were investigated using high resolution transmission electron microscopy (HRTEM), and XRD. Results showed that (1) the as-cast microstructure of the ZA84+Bi-Ca alloy was refined by adding Bi-Ca, and the mechanical properties were improved; (2) when the alloy was aged at 160 °C, the early strengthening phase was spherical Ca2Mg6Zn3 precipitates; as the aging time increased, blocky β1′ and rod-shaped β1′ phases gradually precipitated, greatly improving the aging hardness, and the rod-shaped β1′ precipitates were the main strengthening phase that made the alloy hardness reach the peak and (3) there was an adhesive phenomenon between the tips of the spherical phase and the rod-like phase during aging, which to some extent inhibited the growth of the rod-shaped β1′ precipitates, thus, delaying the aging process.