New orientations between ß2 phase and a matrix in a Mg-Zn-Mn alloy processed by high strain rate rolling

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 [2110]β′2//[0110]α, (0001)β′2//(0001)α, and (0110)β′2//(2110)α to α-Mg matrix. New orientation relationships (for example, [2110]β′2//[0110]α and [0110]β′2~//[2110]α) between the spherical precipitates and α-Mg matrix were firstly observed, and the formation mechanism was systematically discussed.