Microstructural and textural investigation of an Mg–Dy alloy after hot plane strain compression

Abstract

The microstructure and texture development in a Mg–0.41Dy (wt%) alloy after plane strain compression (PSC) at 300 °C under a strain rate of 10−2 and 10−4 s−1 up a final true strain of −1.2 were investigated using electron backscatter diffraction (EBSD) and X-ray diffraction. At high strain rate of 10−2 s−1, the microstructure exhibited massive twins mainly {101¯2} extension, {101¯1} contraction and {101¯3}-{101¯2} double twin due to the random texture of the as-cast alloy. Meanwhile, at a low strain rate of 10−4 s−1, the microstructure was characterized by dynamic recrystallization at the {101¯2} extension, {101¯1} contraction twins and grain boundaries. Twin dynamic recrystallization (TDRX), rotational dynamic recrystallization (RDRX) and discontinuous dynamic recrystallization (DDRX) were the main mechanisms responsible for the formation of recrystallized grains. The texture was characterized by the formation of three fibers: basal , // CD and // CD where CD is the compression direction. Moreover, the texture was less sensitive to the deformation conditions since the recrystallized grains showed the same orientation than twins. The changes of the mechanical properties of the alloy were ascribed to the resulting microstructure due to the twinning and dynamic recrystallization.

Keywords

• Dynamic recrystallization
• PSC
• Mg–Dy alloy
• Texture
• Twinning