Effects of 〈c+a〉 slip mode on microstructure evolution and compressive flow behavior of extruded dilute Mg-0.5Bi-0.5Sn-0.5Mn alloy

The influence of the slip mode on the microstructure evolution and compressive flow behavior at different strains in an extruded dilute Mg-0.5Bi-0.5Sn-0.5Mn alloy was analyzed through electron backscatter diffraction, X-ray diffraction, transmission electron microscopy, and hot compression tests. The results showed that at a low strain of 0.05, the basal 〈 a 〉, pyramidal 〈 a 〉 and 〈 c + a 〉 slip modes were simultaneously activated. Nevertheless, at the middle stage of deformation (strain of 0.1, 0.2 and 0.5), the 〈 a 〉 slip mode was difficult to be activated and 〈 c + a 〉 slip mode became dominant. The deformation process between strains of 0.2 and 0.5 was primarily characterized by the softening effect resulting from the simultaneous occurrence of continuous dynamic recrystallization and discontinuous dynamic recrystallization. Ultimately, at strain of 0.8, a dynamic equilibrium was established, with the flow stress remaining constant due to the interplay between the dynamic softening brought about by discontinuous dynamic recrystallization and the work-hardening effect induced by the activation of the basal 〈 a 〉 slip mode.