Abstract

Alloying with rare-earth (RE) elements enhances the formability of magnesium (Mg) alloys, especially for the lower elevated temperatures. The beneficial effect brought by RE addition is related to texture modification. However, the complexity of the precipitation behavior in RE-containing alloy and the often excessive RE additions has impeded the understanding of the mechanism for RE texture modification. The current study is based on three micro-alloyed Mg-1Zn-xNd (wt.%) alloys with reduced levels of Nd, i.e., x = 0.1, 0.2, and 0.5 wt.%. Two different cooling paths were employed after solutionizing to achieve different precipitation conditions. The alloys were then subjected to hot rolling at 450 °C to a total reduction of 45% in two passes, and post-deformation annealing was also conducted. The precipitation behavior of the current alloy was discussed based on experimental observations and thermodynamic simulations. It was found that “dilute” Nd in solid solution is more effective in suppressing both dynamic and static recrystallization compared to Nd in the form of precipitates. Ultimately, a non-basal texture with basal poles splitting toward rolling direction and transverse direction was obtained for the Mg-1Zn-0.5Nd alloy after annealing. The mechanism of texture weakening effect was attributed to the presence of Nd in solid solution.

中文翻译：

---

冷却路径对微合金镁合金的析出行为，组织和织构演变的影响

摘要

与稀土（RE）元素合金化可增强镁（Mg）合金的可成形性，尤其是在较低的高温下。RE添加带来的有益效果与纹理修饰有关。但是，含RE合金中析出行为的复杂性以及经常添加过量的RE妨碍了人们对RE织构改性机理的理解。当前的研究基于三种Ng含量降低的微合金Mg-1Zn- x Nd（wt。％）合金，即x ＝ 0.1、0.2和0.5重量％。固溶后采用两种不同的冷却路径以实现不同的沉淀条件。然后，将合金在450℃下进行两次热轧至总压下率达45％，并且还进行了变形后退火。基于实验观察和热力学模拟，讨论了当前合金的析出行为。已经发现，与沉淀形式的Nd相比，固溶“稀释”的Nd在抑制动态和静态再结晶方面更为有效。最终，退火后的Mg-1Zn-0.5Nd合金获得了基极向轧制方向和横向分裂的非基体组织。质地减弱作用的机理归因于固溶体中Nd的存在。