引入梯度双模态组织提升挤压态AZ31棒材的拉伸性能

Enhancing tensile properties of extruded AZ31 rod by introducing gradient bimodal microstructure

利用350℃下的往复扭转制备具有梯度双模态显微组织的镁合金棒。详细研究双模态显微组织对合金拉伸性能和变形机制的影响。梯度双模态显微组织的形成归因于不完全动态再结晶和扭转变形的特点。双模态结构对屈服强度的影响较小,但极大增加了峰值应力和拉伸延展性。由梯度双模态显微组织产生的大异质变形诱导的强化是应变硬化能力和拉伸延展性提升的原因。最后,讨论了相关的变形机制。

The Mg alloy rods with a gradient bimodal microstructure were fabricated by forward-reverse torsion at 350℃.The effects of the bimodal microstructure on tensile properties and deformation mechanism of the alloy were investigated in detail.The formation of gradient bimodal microstructure was attributed to the incomplete dynamic recrystallization and the characteristic of torsion deformation.The bimodal structure had less influence on the yield strength but largely increased the peak stress and tension ductility.The large heterogeneous deformation-induced strengthening via gradient bimodal microstructure was responsible for the enhanced strain hardening capacity and tensile ductility.Finally,the related deformation mechanisms were discussed.