(1. 重慶理工大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400050；
2. 重慶大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400044)
摘 要: 本文分析了鎂合金管材普通擠壓成形應(yīng)用發(fā)展的技術(shù)瓶頸和內(nèi)在根源，總結(jié)了各種塑性變形工藝和稀土元素對鎂合金管材組織性能的影響及基本原理、特點(diǎn)。分析了多道次等通道擠壓、平行管道等通道擠壓-反向擠壓等多道次大塑性成形工藝及管材組織特征，發(fā)現(xiàn)多道次大塑性變形可改進(jìn)組織，但成本高、工藝復(fù)雜；綜述了單道次復(fù)合大塑性成形如管狀等通道擠壓、循環(huán)膨脹-擠壓、旋轉(zhuǎn)-反向擠壓、擠壓剪切塑性成形工藝等工藝原理及管材的組織特點(diǎn)，表明單道次復(fù)合大塑性成形工藝簡單；通過在鎂合金中添加微量稀土元素，能夠弱化或隨機(jī)化變形織構(gòu)，強(qiáng)度和塑性都能得到較大提升。論文對鎂合金管材塑性變形工藝的原理進(jìn)行了分析及總結(jié)，指出了采用單道次新型復(fù)合大塑性成形工藝及低稀土鎂合金作為管材材料，進(jìn)行有效的晶界與織構(gòu)設(shè)計(jì)是提高鎂合金管材質(zhì)量的有效途徑，論文對相關(guān)研究進(jìn)行了展望，總結(jié)了目前亟待解決的問題。
關(guān)鍵字: 鎂合金管材；織構(gòu)；微觀組織；大塑性變形
（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
