Tension-compression-tension tertiary twins in coarse-grained polycrystalline pure magnesium at room temperature

Abstract

Using electron backscatter diffraction, the microstructural features of tension–compression–tension (T–C–T) tertiary twins are studied in coarse-grained pure polycrystalline magnesium subjected to monotonic compression along the extrusion direction in ambient air. T–C–T tertiary twins are developed due to the formation of a compression–tension double twin inside a primary tension twin. All the observed T–C–T twin variants are of TiCjTj type. TiCi+1Ti+1 (or TiCi−1Ti−1) variants are observed more frequently than TiCi+2Ti+2 (or TiCi−2Ti−2) variants. The number of tertiary twin lamellae increases with the applied compressive strain.