Acta Metallurgica Sinica (English Letters) ›› 2010, Vol. 23 ›› Issue (1): 63-71.DOI: 10.11890/1006-7191-101-63

• 研究论文 • 上一篇    下一篇

特殊成形工艺下镁合金不同形变机制的取向因子分析

杨平1;王丽娜2;李萧1;孟利2   

  1. 1. 北京科技大学
    2.
  • 收稿日期:2009-09-15 修回日期:2009-12-17 出版日期:2010-02-25 发布日期:2010-02-09
  • 通讯作者: 杨平

Orientation factor analysis of deformation mechanisms under special processing techniques in AZ31 magnesium alloys

Ping YANG1, Lina WANG1,2, Xiao LI1, Li MENG1   

  1. 1. School of Materials Science and Engineering, University of Science and Technology Beijing,Beijing 100083, China
    2. Material Department, School of Tianjin, University of Science and Technology Beijing,Tianjin 301830, China
  • Received:2009-09-15 Revised:2009-12-17 Online:2010-02-25 Published:2010-02-09
  • Contact: Ping YANG

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摘要：

实验表明，异步轧制、等径角挤压以及等径角轧制都可不同程度的削弱镁合金的基面织构，提高塑性，但相应的形变机制并不相同。本文通过计算不同形变机制的取向因子及相对分切应力关系，分析3种特殊成形工艺下的形变特点，考察参数变化造成的影响。分析表明，在异步轧制中，因轧面上切应力的出现，明显减弱产生基面织构的基面滑移和拉伸孪晶，通过产生绕轧板侧向TD转动的基面织构提高塑性；等径角挤压时，沿两通道交角方向切应力的出现促进拉伸孪晶；等径角轧制时，通过轧板表面的剪切力产生沿通道方向的挤压力，最终产生两通道截面上的剪切力而促进拉伸孪晶，其促进程度低于等径角挤压，但通道间隙促进拉伸孪晶。

关键词: magnesium, asymmetrical rolling, equal channel angular pressing, equal channel angular rolling, deformation

Abstract:

Experiments show that special processing techniques such as asymmetrical rolling (ASR), equal channel angular pressing (ECAP) and equal channel angular rolling (ECAR) can weaken the basal texture of the magnesium alloys and therefore improve their plasticity. However, the deformation mechanisms related are different. In this paper, we determine the deformation mechanisms activated during ASR, ECAP and ECAR by calculation of orientation factors. Analysis shows that during ASR the shear stress σ13 on the rolling plane of the samples obviously weakens the basal slip and tension twinning that all produce basal texture and improve plasticity due to the promotion of tilt basal texture. During ECAP the shear stress  σs on the intersecting plane of two channels promotes tension twinning in the basal
oriented grains, whereas under ECAR the shear stress σ13   induced by roller friction on the rolling plane produces the shear stress  σs on the intersection plane of the two channels that also promotes tension twinning. Although the shear strain is lower in ECAR than in ECAP, the channel clearance in ECAR facilitates tension twinning.

Key words: Magnesium, Asymmetrical rolling, Equal channel angular pressing, Equal channel angular rolling, Deformation