(1. 重庆理工大学 材料科学与工程学院，重庆 400050；
2. 重庆大学 材料科学与工程学院，重庆 400044)
摘 要: 为了提高AZ31镁合金板材的力学性能，结合普通挤压成形与大塑性剪切成形的特点提出了挤压-剪切新型复合变形方式。采用DEFORM-3D软件对板材的挤压-剪切过程进行数值模拟，探索塑性变形机理，研究成形过程中温度场、速度场以及成形载荷的演变规律。结果表明：成形过程中较大温升主要集中在剪切区域，最大温升约为6 ℃；随着温度的升高，成形载荷逐渐降低，金属的流动速度加快，且内部流速明显大于外部；经过挤压-剪切成形后板材的晶粒得到明显细化，并且随着挤压温度的升高，晶粒逐渐长大；挤压-剪切成形使得板材表面硬度明显升高，挤压温度为330 ℃、370 ℃和410 ℃时，板材的硬度分别为77 HV、75 HV、72 HV。挤压-剪切工艺是一种新型的板材成形工艺，细化了板材的晶粒尺寸，提高了板材的力学性能。
关键字: 镁合金；板材；数值模拟；热挤压；力学性能
（1. School of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400050, China;
2. School of Materials Science and Engineering, Chongqing University, Chongqing 400044, China）
Abstract:In order to improve the mechanical properties of AZ31 magnesium alloy sheet, the extrusion-shear composite deformation process was proposed by combining the characteristics of direct extrusion and continuous shearing. The extrusion-shear forming process of sheet was simulated by DEFORM-3D software. The plastic deformation mechaism was explored, and the evolution laws of temperature fields, velocity fields and forming loads during the forming process were studied. The results show that the lager temperature rise is mainly concentrated in the shearing zone during forming process, and the value of temperature rise is about 6 ℃. With the increase of temperatures, the forming load decreases gradually, and flow velocities of metal quickens, and internal flow velocities are obviously higher than those of outside. The microstructures of sheets are refined obviously after extrusion-shear forming process. With the increase of temperature, the grains grow gradually. The hardnesses of sheet surfaces prepared by extrusion-shear forming process increase obviously. When the extrusion temperatures are 330 ℃, 370 ℃ and 410 ℃, the hardnesses of the formed sheets are 77 HV, 74 HV and 72 HV, respectively. The extrusion-shear process is a new sheet forming process, which refines the grain sizes of sheets and improves the mechanical properties of sheets.
Key words: magnesium alloy; sheet; numerical simulation; extrusion-shear plate; mechanical property
