New orientations between β′2 phase and α matrix in a Mg-Zn-Mn alloy processed by high strain rate rolling

Abstract

Strengthening precipitates in a Mg-Zn-Mn alloy, processed by high strain rate rolling, have been characterized by transmission electron microscopy. Precipitations involve a few (0001)α plates and spherical precipitates. All the precipitates have a hexagonal structure of MgZn2 and can be defined as β′2 phase. The (0001)α plates and a portion of the spherical precipitates have a common orientation relationship of [2¯110]β2'//[011¯0]α, (0001)β2'//(0001)α and (011¯0)β2'//(2¯110)α to α-Mg matrix. New orientation relationships (for example, [2¯110]β2'//[011¯0]α and (011¯5)β2'∼//(2¯110)α) between the spherical precipitates and α-Mg matrix were firstly observed, and the formation mechanism was systematically discussed.