Hot Compression Behavior of Mg-10Gd-2Y-1Zn-0.5Zr Alloy and Abnormal Poor Formability at High Temperature
摘要
The hot deformation behavior of a high strength Mg-10Gd-2Y-1Zn-0.5Zr alloy was investigated by performing hot compression at various temperatures (300-500 °C) and strain rates (0.01-5 s−1). A processing map, constructed based on the obtained stress–strain curves and the dynamic material model, was established. The results indicate that the optimal deformation temperature lies between 450 °C and 500 °C, with a suitable strain rate range of 0.01-0.1 s−1. The post-deformation morphology and microstructure of the specimens were characterized. At high strain rates (5 s−1 and 1 s−1), the workability of the Mg-10Gd-2Y-1Zn-0.5Zr alloy initially increases and subsequently decreases with rising temperature, contradicting conventional expectations. This anomalous phenomenon is attributed to strain localization induced by the combined effects of high strain rates (5 and 1 s−1) and elevated temperature (500 °C), which exceed the material's plasticity limit under these conditions, resulting in crack formation. These findings provide theoretical guidance for the plastic forming of Mg-Gd-Y-Zn-Zr alloys.