轧制-剪切-弯曲变形AZ31镁合金板材的表面质量缺陷与机理研究  

Study on surface quality defects and mechanism of AZ31 magnesium alloy sheet by rolling-shearing-bending deformation

作　　者：蒋伟[1] 周涛[1,2] 宋登辉 范恒瑞[1] 邱泽林 

机构地区：[1]重庆理工大学材料科学与工程学院,重庆400054 [2]重庆理工大学重庆市模具工程技术研究中心,重庆400054

出　　处：《锻压技术》2017年第1期27-32,共6页Forging & Stamping Technology

基　　金：国家自然科学青年基金资助项目(51301213);重庆市基础与前沿研究计划项目(cstc2014jcyj A50008;cstc2016jcyj A0452)

摘　　要：通过分析轧制-剪切-弯曲AZ31镁合金板材的裂纹特征,并采用有限元数值模拟和金相观测,研究了不同通道间隙下AZ31镁合金板材表面质量缺陷与应力、应变、模具弯曲半径、微观组织结构的关系。结果表明:板材易在第2弯曲转角处出现非连续横向裂纹,同时模具进口平面处板材易发生连续的起皱现象;随着通道间隙的增大,模具转角处应力、应变值逐渐变小,网格畸变程度逐渐降低,同时第2弯曲转角半径的增大也有利于制备出表面质量良好的AZ31镁合金板材;由于轧制、剪切、弯曲变形的应力、应变积累过大,裂纹主要出现在剪切带相对集中、孪晶交叉较多的区域,裂纹的拓展主要在孪晶界附近。Through the crack characteristic analysis of rolling-shearing-bending for AZ31 magnesium alloy sheet,and by using the finite element numerical simulation and metallographic observation,the relationships among the stress,strain,die bending radius,microstructure and the surface quality defects of AZ31 magnesium alloy sheet with different channel clearances were studied. The results show that the plate easily appears discontinuous transverse cracks in the second bending corner. At the same time,the phenomenon of continuous wrinkling occurs at the sheet of import plane of die. With the increase of channel clearance,the stress and strain at the corner of die gradually become smaller,and the mesh distortion is gradually reduced. The increase of the radius of the second bending corner is also beneficial to the preparation of AZ31 magnesium alloy sheet with good surface quality. Because the accumulation of stress and strain is too large which is caused by rolling-shearing-bending deformation,the cracks mainly appear in the region where the shear zone is relatively concentrated and the twin intersections are more,and the crack propagation is mainly near the twin boundaries.

关 键 词：轧制-剪切-弯曲变形 AZ31镁合金 裂纹 表面质量缺陷 通道间隙 

分 类 号：TG339[金属学及工艺—金属压力加工] TG146.22[一般工业技术—材料科学与工程]