预置拉伸孪晶诱发动态再结晶的镁合金晶粒细化机制

项目名称： 预置拉伸孪晶诱发动态再结晶的镁合金晶粒细化机制

项目编号： No.51504162

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 矿业工程

项目作者： 张华

作者单位： 太原理工大学

项目金额： 22万元

中文摘要： 本项目以具有基面织构的AZ31镁合金轧制板材为研究对象，通过预变形预置{10-12}<10-11>拉伸孪晶，在随后热压缩变形过程中利用预置拉伸孪晶加速动态再结晶进程以实现晶粒细化，提出了预置拉伸孪晶诱发动态再结晶制备细晶镁合金材料的新方法。项目将研究热压缩变形过程中预置拉伸孪晶对变形孪生、位错运动、亚结构变化以及变形织构转变等的影响，获得组织演变规律；考察晶界、亚晶界及孪晶界等晶粒形核区域的组织特征，研究预置拉伸孪晶诱发的动态再结晶晶体学行为、动态再结晶形核机制，揭示预置拉伸孪晶诱发的晶粒细化机制；定量研究预置拉伸孪晶对动态再结晶晶粒细化效果的影响，并结合热压缩工艺参数，获得最优化预置拉伸孪晶诱发的晶粒细化效应。项目研究成果对细晶镁合金材料的制备具有重要的理论价值与实际应用意义，将为提升镁合金性能，扩展镁合金应用展示一条新途径。

中文关键词： 镁合金；拉伸孪晶；动态再结晶；晶粒细化；力学性能

英文摘要： This project regards the rolled AZ31 magnesium alloy sheet with basal texture as the research object, and {10-12}<10-11> tensile twins introduced by pre-deformation are used to accelerate the dynamic recrystallization process during subsequent warm compression deformation to achieve grain refinement, thus proposing a method for preparing fine-grained magnesium alloy by dynamic recrystallization induced by pre-introducing tensile twins. The project will study effects of pre-introducing tensile twins on deformation twinning, dislocation movement, substructure changes and deformation texture transformation during warm compression deformation to obtain the evolution law of microstructure. The microstructure characteristics in grain nucleation region such as grain boundaries, sub-boundaries, twin boundaries etc. will be examined, and then the crystallography behaviors and nucleation mechanisms of dynamic recrystallization induced by pre-introducing tensile twins will be studied to reveal the grain refinement mechanisms. The present work will also quantitatively study effects of pre-introducing tensile twins on grain refinement by dynamic recrystallization, and combine the warm compression process parameters in order to obtain the optimal grain refinement effect induced by pre-introducing tensile twins. The research results have important theoretical value and practical application significance to preparing of fine-grained magnesium alloy. It will show a new way for improving properties of magnesium alloy and expanding its application.

英文关键词： Magnesium alloy;Tensile twins;Dynamic recrystallization;Grain refinement;Mechanical properties