Microstructure evaluation and thermal deformation behaviours of wrought magnesium alloys

Due to the large orientation gradient, the dynamic recrystallisation of Mg–Zn–Nd–Zr wrought alloy occurred first around grain boundaries. The Nd-rich second phase promoted the nucleation of recrystallisation. With the increasing strain, more non-basal plane slip occurred near the grain boundary, which caused the adjacent subgrain boundary merging into a high angle grain boundary. In addition, some twin intersecting regions gathered high-density dislocation, leading to twin dynamic recrystallisation. By deducing the stress–strain constitutive relation during thermal deformation and analysing the relation between the apparent value of constant creep exponent (n) and the corresponding deformation mechanism, the dominant mechanism of dislocation sliding and climbing during dynamic recrystallisation was deduced backwards.