Microstructure evolution of Mg–14% Li–1% Al alloy during the process of equal channel angular pressing

The super-light Mg–14% Li–1% Al alloy was produced and processed by conventional extrusion at 573 K and further by equal channel angular pressing (ECAP) at room temperature (RT). The microstructure evolution of the alloy during the ECAP treatment was investigated by transmission electron microscope (TEM). The results showed that the grains of the matrix β phase were substantially refined, with the mean size decreasing from 60 μm to 200 nm. The distribution of the α precipitates, which were embedded in the β grains, and the ternary MgLiAl2 phase coexisting with the α precipitates was homogenized by ECAP processing. The existence of the MgLiAl2 phase was consolidated by both X-ray diffraction (XRD) analyses and TEM observations.