Grain refinement of magnesium alloys processed by severe plastic deformation  

大塑性变形镁合金的晶粒细化(英文)

作　　者：陈勇军[1,2,3] 王渠东[1] 林金保[4] 刘满平[5] Jarle HJELEN Hans J.ROVEN 

机构地区：[1]上海交通大学 轻合金精密成型国家工程研究中心,上海200030 [2]Department of Materials Science and Engineering, Norwegian University of Science and Technology [3]ERC for Revolutionizing Metallic Biomaterials, North Carolina A&T State University [4]太原科技大学 应用科学学院,太原030024 [5]江苏大学 材料科学与工程学院,镇江212013 [6]Center for Advanced Materials, Qatar University

出　　处：《Transactions of Nonferrous Metals Society of China》2014年第12期3747-3754,共8页中国有色金属学报（英文版）

基　　金：Projects(50674067,51074106,51374145)supported by the National Natural Science Foundation of China;Project(09JC1408200)supported by the Science and Technology Commission of Shanghai Municipality,China;Project(2011BAE22B01-5)supported by the National Key Technology R&D Program of China;Projects(182000/S10,192450/I30)supported by the Research Council of Norway

摘　　要：Grain refinement of AZ31 Mg alloy during cyclic extrusion compression （CEC） at 225-400 ℃ was investigated quantitatively by electron backscattering diffraction （EBSD）. Results show that an ultrafine grained microstructure of AZ31 alloy is obtained only after 3 passes of CEC at 225 ℃. The mean misorientation and the fraction of high angle grain boundaries （HAGBs） increase gradually by lowering extrusion temperature. Only a small fraction of {101^-2} twinning is observed by EBSD in AZ31 Mg alloys after 3 passes of CEC. Schmid factors calculation shows that the most active slip system is pyramidal slip {101^-1}〈1120〉and basal slip {0001}〈1120〉 at 225-350 ℃ and 400 ℃, respectively. Direct evidences at subgrain boundaries support the occurrence of continuous dynamic recrystallization （CDRX） mechanism in grain refinement of AZ31 Mg alloy processed by CEC.采用电子背散射技术（EBSD）定量研究AZ31镁合金在225-400℃往复挤压大变形过程中的晶粒细化。结果表明：在225℃往复挤压3道次即获得了超细晶AZ31镁合金。随着变形温度的降低,变形组织的平均位相差和大角度晶界的比例逐渐增加。在3道次的AZ31组织中,只发现少量的{101^-2}孪晶,位错滑移是主要的变形机制。施密特因子计算表明,在225-350℃变形时,锥面滑移系{101^-1}〈112^-0〉被大量激活。而在400℃变形时,基面滑移系{0001}〈112^-0〉被大量激活。亚晶界的详细分析为连续动态再结晶在镁合金大变形过程中晶粒细化的重要作用提供了直接的证据。

关 键 词：magnesium alloys grain refinement continuous dynamic recrystallization （CDRX） electron backscattering diffraction（EBSD） cyclic extrusion compression （CEC） 

分 类 号：TG146.22[一般工业技术—材料科学与工程]