Role of yttrium in the microstructure and texture evolution of Mg

Single-phase solid solution alloys, Mg–2.9Y and Mg–2.9Zn (in wt%), and two-phase (α-Mg solid solution + intermetallic) Mg–Zn–Y alloys were deformed in uniaxial hot compression (350 °C) to investigate the origin of texture weakening upon the addition of Y rare earth element into Mg. The separate effects of the type of solutes and intermetallics during deformation and subsequent isothermal annealing were studied via X-ray texture measurement and EBSD techniques. It was found that the ternary Mg–5Zn–2Y and Mg–6Zn–1.2Y alloys exhibit recrystallization of new grains at intermetallics. Furthermore, the progress of dynamic recrystallization with straining is severely retarded in the Mg–2.9Y alloy, with respect to all the other alloys. A nearly similar basal texture develops in all the alloys at the strain of 1 (i.e., steady state region of flow curves) despite the difference observed in the volume fraction of dynamically recrystallized grains. On subsequent annealing of the as-deformed alloys, a significant increase in the average size of the recrystallized grains is observed, but the texture is weakened only in the Mg–2.9Y alloy.