(1. 重庆理工大学 材料科学与工程学院，重庆 400050；
2. 重庆大学 材料科学与工程学院，重庆 400044)
摘 要: 本文分析了镁合金管材普通挤压成形应用发展的技术瓶颈和内在根源，总结了各种塑性变形工艺和稀土元素对镁合金管材组织性能的影响及基本原理、特点。分析了多道次等通道挤压、平行管道等通道挤压-反向挤压等多道次大塑性成形工艺及管材组织特征，发现多道次大塑性变形可改进组织，但成本高、工艺复杂；综述了单道次复合大塑性成形如管状等通道挤压、循环膨胀-挤压、旋转-反向挤压、挤压剪切塑性成形工艺等工艺原理及管材的组织特点，表明单道次复合大塑性成形工艺简单；通过在镁合金中添加微量稀土元素，能够弱化或随机化变形织构，强度和塑性都能得到较大提升。论文对镁合金管材塑性变形工艺的原理进行了分析及总结，指出了采用单道次新型复合大塑性成形工艺及低稀土镁合金作为管材材料，进行有效的晶界与织构设计是提高镁合金管材质量的有效途径，论文对相关研究进行了展望，总结了目前亟待解决的问题。
关键字: 镁合金管材；织构；微观组织；大塑性变形
（1. School of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400050, China;
2. School of Materials Science and Engineering, Chongqing University, Chongqing 400044, China）
Abstract:The paper analyzed the technical bottlenecks and internal sources of the applications and development of direct extrusion forming of magnesium alloy tubes. And the effects of various plastic deformation processes and rare earth elements on microstructures and properties of magnesium alloy tube were summarized, as well as the basic principles and characteristics. The multi-pass large plastic forming processes, such as multi-pass equal channel extrusion, parallel channel extrusion and reverse extrusion, and the microstructures characteristics of tubs were analyzed. It was found that multi-pass severe plastic deformation could improve the microstructures, but the cost is high and the process is complicated. The principle of single pass composite large plastic forming, such as tubular equal channel extrusion, cyclic expanding-extrusion, rotation-reverse extrusion, extrusion-shear plastic forming, and the microstructure characteristics of tube were reviewed. By adding trace rare earth elements into the magnesium alloy, the deformation textures were weakened or randomized, and the anisotropies of tubes were improved, and the strengths and plasticity can be improved greatly. The principles of plastic deformation processes of magnesium alloy tubes were analyzed and summarized. It is pointed out that the effective design of grain boundaries and textures are effective ways to improve the qualities of magnesium alloy tube by adopting the new single pass composite large plastic forming process and low rare earth magnesium alloy as tube material. Related researches were prospected, and the problems to be solved at present were summarized.
Key words: magnesium alloy tube; texture; microstructures; large plastic shear deformation
