Effect of Y content on the microstructure and mechanical anisotropy of Mg–6Zn-xY-0.5Ce-0.4Zr alloy subjected to asymmetric rolling

Abstract

An in-depth study of the anisotropic mechanical behavior of Mg alloys is essential for optimizing mechanical properties, designing high-performance Mg alloys, and developing processing processes. This work investigates the microstructure and mechanical anisotropy of Mg–6Zn-xY-0.5Ce-0.4Zr (MZCZ-xY) alloys with varying Y contents subjected to asynchronous rolling (ASR). The Y content significantly affects the microstructure and mechanical anisotropy of the MZCZ-xY alloy. In lower Y content alloys (MZCZ-0.2Y, MZCZ-0.5Y), the second phase mainly consists of Mg3Zn6Y (I phase) and Mg1.5Zn9.5Ce3, while the addition of 1.0 wt% Y leads to the appearance of Mg3Zn3Y2 (W phase) in the alloy. Furthermore, increasing Y content results in grain growth in the as-cast state, which will affect the average grain size after asymmetric rolling (ASR) deformation. However, alloys with higher Y content exhibit a more pronounced effect of grain refinement at the same ASR strain. Moreover, increasing Y content promotes the activation of tensile twins, with higher Y content leading to greater tensile twin activation after ASR treatment. The MZCZ-0.2Y alloy shows lower mechanical anisotropy, which is closely related to the homogeneous texture component and uniform Schmid factor (SF) in each loading direction. Therefore, the regulation of mechanical anisotropy in Mg alloys can be achieved by obtaining uniform texture components and uniform SF in each loading direction.