AZ31镁合金不同挤压速度下的组织演变及力学性能研究  

Microstructure Evolution and Mechanical Properties of AZ31 Magnesium Alloy at Different Extrusion Velocities

作　　者：韩修柱[1,2] 田政[1] 臧晓云 肖阳[3] 张高龙 于洋 HAN Xiu-zhu;TIAN Zheng;ZANG Xiao-yun;XIAO Yang;ZHANG Gao-long;YU Yang(Beijing Institute of Spacecraft System Engineering,Beijing 100094,China;Harbin Institute of Technology,Harbin 150001,China;Zhengzhou Qingyan Alloy Technology Co.,Ltd.,Zhengzhou 450041,China;Tianjin Aerospace Electromechanical Equipment Research Institute,Tianjin 300301,China)

机构地区：[1]北京空间飞行器总体设计部,北京100094 [2]哈尔滨工业大学材料科学与工程学院,哈尔滨150001 [3]郑州轻研合金科技有限公司,郑州450041 [4]天津航天机电设备研究所,天津300301

出　　处：《精密成形工程》2022年第6期10-19,共10页Journal of Netshape Forming Engineering

基　　金：装备预先研究项目(50922010302);中国空间技术研究院“杰青”人才项目。

摘　　要：目的针对AZ31镁合金材料在挤压成形过程中变形较为困难的问题,研究AZ31镁合金在不同挤压速度下的微观组织和力学性能演化规律。方法采用DEFORM-2D软件对0.5、3、12、20 mm/s这4种挤压速度下材料挤压变形过程中的材料流动趋势、应变场、应力场和温度场等进行数值模拟和分析。结果AZ31镁合金材料的挤压温度场随着挤压速度的增加显著升高,不同速度挤压后坯料的温度模拟值与实验结果实测值的变化趋势吻合。随着挤压速度的增大,材料的晶粒尺寸先增大后减小,0.5、3、12、20 mm/s这4种速度挤压后的晶粒尺寸分别为1.0、0.9、1.4、1.1μm,变形材料的加工硬化率呈现出先增大后减小的趋势。在0.5 mm/s的挤压速度下,材料内部的微观组织均匀性较差,然而强度较高,抗拉强度约为416 MPa;在挤压速度为12 mm/s时,合金的晶粒组织最均匀,同时其综合力学性能较好,屈服强度为220 MPa,伸长率为17.3%,其加工硬化率也达到最大,为0.184。结论通过DEFORM数值模拟能够为镁合金挤压变形提供指导。对于镁合金挤压变形,采用较低的挤压速度(约0.5 mm/s)对AZ31镁合金进行挤压变形,能够获得强度较高、伸长率相对偏低的挤压棒材,采用较高的挤压速度(约12 mm/s),则更有利于获得综合性能优良的镁合金挤压棒材。According to the demand of spacecraft and relatively difficult of extrusion of AZ31 magnesium alloy,the paper aims to reveal the microstructure evolution and mechanical behaviors of AZ31 magnesium alloy at different extrusion speeds.the DEFORM-2D software is used to study the numerical simulation and analysis of material deformation and flow tendency at extrusion velocities of 0.5,3,12,20 mm/s.The results show that the temperature field of extruded AZ31 magnesium alloy increases obviously with the increase of extrusion speed,and the simulation result of the temperature at different speeds is in good agreement with the measured value of the extruded AZ31 magnesium alloy.With the increase of extrusion speed,the grain size of the alloy increases at first and then decreases.The grain sizes of 0.5,3,12,20 mm/s are 1.0,0.9,1.4,1.1μm respectively,and the work hardening rate of the extruded alloy also increases at first and then decreases.At the extrusion speed of 0.5 mm/s,the microstructure is less homogeneous,but the strength is higher.The ultimate tensile strength is 416 MPa.At the extrusion speed of 12 mm/s,the microstructure of the alloy is relatively homogeneous,the tensile yield strength and elongation are 220 MPa and 17.3%,respectively.The work hardening rate is 0.184.The numerical simulation method of DEFORM can provide guidance for the extrusion process of AZ31 magnesium alloy.The extruded alloy with high strength and low elongation can be obtained through extrusion process at the low extrusion speed(~0.5 mm/s).Nevertheless,the extruded alloy with excellent comprehensive properties can be obtained during extrusion process at the relatively extrusion speed(~12 mm/s),which suggests the advantage of the high extrusion speed in the extrusion process of the AZ31 magnesium alloy.

关 键 词：挤压速度 AZ31镁合金 组织 力学性能 

分 类 号：TG302[金属学及工艺—金属压力加工]