镁合金塑性变形中孪生的研究

介绍了镁合金变形过程中孪生的晶体学、位错机理以及几何位向学;探讨了孪晶的形核、长大与演变机制;分析了孪生过程对塑性变形的作用;论述了影响孪生的几种基本因素,包括晶粒取向、变形温度、变形速度、晶粒尺寸、预变形.研究结果表明,镁合金塑性变形过程中孪生变形的作用在于,通过孪生过程改变晶粒取向或通过孪晶间或孪晶与滑移之间的相互作用,诱发新的滑移和孪生;孪晶也可抑制裂纹的产生和扩展,从而提高变形镁合金的室温塑性.

Investigation of the Twinning in Plastic Deformation of Magnesium Alloy

The crystallology, dislocation mechanism and geometry of twinning during plastic deformation of magnesium alloys are overviewed in this paper. And then, the nucleation, growth and evolution mechanism of deforma tion twins are discussed. The effect of twinning on plastic deformation is presented. The influences of material variables on twinning, including crystal orientation, temperature, strain rate, grain size and prestrain, are analyzed. It can be concluded that new sliding or twinning may be promoted by twinning which can alter the crystal orientation, or by the twin-twin interactions or twin-sliding interactions, and twinning may also restrain the initiation and propagation of cracks, then the plasticity of magnesium alloys at room temperature is improved.