两步等通道角挤压AZ31镁合金的微观组织和力学性能

The Microstructure and Mechanical Properties of AZ31 Mg Alloy Processed by Two-Step Equal Channel Angular Extrusion

对AZ31镁合金经等通道角挤压(ECAE)变形后的微观组织和力学性能进行了研究.结果表明:在498～523 K温度范围内变形后,合金晶粒随着变形程度增加明显细化,延伸率提高,但屈服强度降低;随着变形温度降低,变形后合金的延伸率下降,而屈服强度有所提高.基于以上两点规律提出了两步ECAE工艺,在两步ECAE变形过程中,AZ31合金的变形温度可以降低至453 K,经两步ECAE变形后,获得亚微米级的亚结构AZ31镁合金的强韧性随之得到明显的改善.

The microstructure and mechanical properties of AZ31 Mg alloy processed by equal channel angular extrusion（ECAE） were investigated. The results show that after the extrusion of four or five passes at 498-523K, the ductility increases due to grain refinement but the strength decreases. And the elongation increases and the strength decreases with the increase of processing temperature. Therefore, a new ECAE processing, two-step ECAE, was applied to control the microstructure and mechanical properties of AZ31 Mg alloy. The ultra-fine grain of 0.5/zm could be produced, and both the ductility and yield stress of the alloy are significantly improved after the processing.