(1. 湖南科技大学 高功效轻合金构件成形技术及耐损伤性能评价湖南省工程研究中心，湘潭 411201；
2. 湖南科技大学 高温耐磨材料及制备技术湖南省国防技术重点实验室，湘潭 411201；
3. 宁波大学 机械工程与力学学院，宁波 315211)
摘 要: 本文以预孪晶AZ31镁合金为研究对象，结合黏塑性自洽(VPSC)模型仿真，研究中温高速冲击下预孪晶镁合金的变形机理和力学行为，拓展了VPSC模型的应用领域，为研究镁合金动态载荷下的变形机理和力学行为提供了新的手段。结果表明：中温高速冲击过程中，基面滑移和二阶锥面滑移是协调变形的主要机制，孪生也起到了重要的作用；大量孪晶的出现引起流变应力在变形初期发生波动；压缩孪晶的出现引起织构最大极密度位置向半径方向(Radial direction, RD)偏转，二次孪晶的产生有利于形成双峰织构。
关键字: AZ31镁合金；中温高速冲击；黏塑性自洽模型；力学行为；预孪晶；织构
（1. Hunan Engineering Research Center of Forming Technology and Damage Resistance Evaluation for High Efficiency Light Alloy Components, Hunan University of Science and Technology, Xiangtan 411201, China;
2. Key Laboratory of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province, Hunan University of Science and Technology, Xiangtan 411201, China;
3. Faculty of Mechanical Engineering and Mechanics, Ningbo University, Ningbo 315211, China）
Abstract:The deformation mechanism and mechanical behavior of pre-twinning AZ31 magnesium alloy under medium temperature with high speed impacting were investigated by combining the simulation of visco-plastic self-consistent (VPSC) model. This expanded the applications of VPSC model and provided a new approach to study the deformation mechanism and mechanical behavior of magnesium alloy under dynamic loading. The results show that during the medium temperature impacting, basal slip and second-order pyramidal slip are the dominant accommodation mode, and twinning also plays an important role. The flow stress fluctuates due to the occurrence of numerous twins. The maximum intensity position rotates toward RD for the onset of contraction twins. Double peak texture forms attributing to the activation of secondary twins.
Key words: AZ31 magnesium alloy; medium temperature impacting; visco-plastic self-consistent model; mechanical behavior; pre-twinning; texture
