等轴晶AZ80镁合金的全场晶体塑性模拟研究  

Full-field Crystal Plasticity Simulation of Equiaxed AZ80 Magnesium Alloy

作　　者：胡鸿彪 徐帅 章海明 金朝阳[1] HU Hongbiao;XU Shuai;ZHANG Haiming;JIN Zhaoyang(School of Mechanical Engineering,Yangzhou University,Yangzhou 225100,Jiangsu,China;School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200030,China)

机构地区：[1]扬州大学机械工程学院,江苏扬州225100 [2]上海交通大学材料科学与工程学院,上海200030

出　　处：《材料导报》2024年第9期237-242,共6页Materials Reports

基　　金：国家自然科学基金(51901202)。

摘　　要：对铸态AZ80镁合金进行405℃,24 h的固溶处理、等径角挤压(Equal channel angular pressing,ECAP)实验,并使用全场晶体塑性模拟(Full-field crystal plasticity simulation)探究试样在拉伸变形过程中的微观演化。晶体塑性模拟可以更加便捷地获得相对准确的微观变形机制、孪晶演变等更加全面的现场数据,以此总结出不同物理量的规律,这些优势在实验表征过程中是较难实现的,且在追踪试样变形过程中起到重要作用。研究发现,试样经ECAP之后会形成细晶均匀组织,屈服强度和抗拉强度分别达到215.1 MPa、381.5 MPa,延伸率为20.1%,显著高于铸态AZ80的性能(屈服强度为118.6 MPa,抗拉强度为162.68 MPa,延伸率为6.6%);同时通过模拟可以很好地预测不同应变量下镁合金微观组织和变形机制的演化规律,发现随着应变的增加,内部出现拉伸孪晶的晶粒中会发生Basinski效应,同时在硬取向区域形成剪切带;在变形过程中,基面滑移是主要变形机制,并在拉伸达到4%时其对变形的贡献有所下降,其下降部分主要由柱面滑移补偿。The as-cast AZ80 magnesium alloy was subjected to solid solution treatment at 405℃for 24 hours,ECAP experiments,and the micro-evolution of the sample during tensile deformation was investigated using full-field crystal plasticity simulation.More comprehensive field data such as relatively accurate microscopic deformation mechanism and twin evolution can be obtained more conveniently by crystal plasticity simulation,and the laws of different physical quantities can be summarized accordingly.These advantages are difficult to achieve in the experimental characterization process,and play an important role in tracking the deformation process of the sample.It was found that after ECAP,the sample would form a small grain uniform structure.The yield strength and tensile strength reached 215.1 MPa and 381.5 MPa,respectively,and the plasticity was 20.1%,which was significantly higher than that of as-cast AZ80(yield strength 118.6 MPa,tensile strength 162.68 MPa,plasticity 6.6%).At the same time,the simulation can well predict the evolution of microstructure and deformation mechanism of magnesium alloy under different strain variables.It is found that with the increase of strain,Basinski effect will occur in the grains with tensile twins,and shear bands will be formed in the hard-oriented region.In the deformation process,the basal slip is the main deformation mechanism,and the contribution to the deformation decreases when the strain reaches 4%,which is mainly compensated by the prismatic slip.

关 键 词：AZ80 细晶 等径角挤压 全场晶体塑性模拟 

分 类 号：TG146.22[一般工业技术—材料科学与工程]