塑性变形中晶粒变形与细化机制的影响因素

Influence Factors on Grain Deformation and Refinement Mechanisms during Plastic Deformation

讨论了层错能、应变速率和变形温度等因素在塑性变形制备超细晶/纳米晶材料的变形过程中,对变形机制与晶粒细化机制的影响。研究表明,随着层错能的降低,晶粒的变形机制会由位错滑移向机械孪生转变,有利于晶粒的细化。应变速率的增加与变形温度的降低有利于抑制位错动态回复、增加流变应力,促使晶粒进一步细化。

With the development of techniques for preparing ultrafJne-graJned and nanostructured materials in the past decades, the microstructures of ultrafine-grained and nanostructured materials were wideJy investigated due to their unique microstructures and superior properties. The JnfJuences of stacking fault energy, stain rate and deformation temperature during plastic deformation were discussion. The results show： as the stacking fault energy reduces, the dominated plastic deformation mechanism changes from dislocation slipping to mechanical twinning. It is benefit to refine grain. Increasing strain rate and reducing deformation temperature are helpful to suppress dynamic recovery and enhance flow stress, which lead to form grains with smaller sizes.