Deformation induced dynamic recrystallization and precipitation strengthening in an MgZnMn alloy processed by high strain rate rolling

The microstructure of a high strain-rate rolled MgZnMn alloy was investigated by transmission electron microscopy to understand the relationship between the microstructure and mechanical properties. The results indicate that: (1) a bimodal microstructure consisting of the fine dynamic recrystallized grains and the largely deformed grains was formed; (2) a large number of dynamic precipitates including plate-like MgZn2 phase, spherical MgZn2 phase and spherical Mn particles distribute uniformly in the grains; (3) the major facets of many plate-like MgZn2 precipitates deviated several to tens of degrees (3°-30°) from the matrix basal plane. It has been shown that the high strength of the alloy is attributed to the formation of the bimodal microstructure, dynamic precipitation, and the interaction between the dislocations and the dynamic precipitates.