Microstructure and Texture Evolution of AZ31 Magnesium Alloy Thin Sheet Processed by Hot‐Rolling–Shearing–Bending

2021 
A novel and efficient deformation methodology, viz., hot-rolling–shearing–bending (HRSB), to introduce a large amount of $$\{ 10\bar {1}2\}$$ extension twins (ETs) and control the texture of the AZ31 magnesium alloy thin sheet was proposed. Microstructure and texture within various regions of the thin sheet fabricated by the HRSB method were investigated by means of electron back-scattered diffraction measurement. The experimental results indicated that using only single pass of HRSB, grains with c-axis//normal direction (ND) in as-received sheet are nearly twinned totally (about 91% volume fraction of $$\{ 10\bar {1}2\}$$ ET), leading to the formation of c-axis//rolling direction (RD) texture component and the disappearance of c-axis//ND texture component. As for the HRS sample which has suffered from rolling–shearing deformation, both a tensile stress component deriving from the shearing deformation and a compressive stress component resulting from the impediment effect of the mould structure are beneficial to activate $$\{ 10\bar {1}2\}$$ ET, the volume fraction of which is about 72%. With respect to the HRSB sample which has undergone rolling–shearing–bending deformation, the further increase in volume fraction of $$\{ 10\bar {1}2\}$$ ET might be mainly related to the resultant compressive stress of the tensile stress derived from the bending deformation and the compressive stress resulting from the impediment effect of mould structure. It would hinder the activation of $$\{ 10\bar {1}2\}$$ ET within twinned areas and promote the migration of existing boundaries of $$\{ 10\bar {1}2\}$$ ET into un-twinned areas.
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