The effect of twin-twin interaction in Mg3Al1Zn alloy during compression

Electron backscattered diffraction serial image analyses on AZ31 magnesium alloy compressed along RD at different strain levels revealed that twin-twin interactions are found to correlate with mechanical hardening. Four typical twin-twin structures are investigated: (1) Parallel twins with single variant; (2) Interacting twins with single variant; (3) Parallel twins with double variants; (4) Interacting twins with double variants. We studied twin-twin interactions by combining experimental observations and Schmid factor analysis. Due to twins intersecting with each other, the limited growth rate of twins was observed in EBSD maps. The intersection between different twin variant pairs was found to retard the twin growth and promote the nucleation of new twins near intersection region. Besides, “Apparent crossing” twin structure is a limiting case, in which the twin is crossed by a couple of twins, and the interaction region grow slowly. Twin-twin boundary migration is also observed during deformation in this paper, which is considered as an important cause to prohibit twins for further propagate and growth. All these features can be related to twinning-induced hardening.