AZ31镁合金板材连续挤压数值模拟与实验研究  

Numerical simulation and experimental study on continuous extrusion of AZ31 magnesium alloy sheet

作　　者：李智勇 裴久杨[1] 郭丽丽[1] 王延辉[1] Li Zhiyong;Pei Jiuyang;Guo Lili;Wang Yanhui(Continuous Extrusion Engineering Research Center of Education Ministry, Dalian Jiaotong University, Dalian 116028 , China)

机构地区：[1]大连交通大学连续挤压教育部工程研究中心

出　　处：《锻压技术》2019年第7期15-20,共6页Forging & Stamping Technology

基　　金：国家自然科学基金青年基金项目(51401043);大连市科技之星项目(2017RQ139)

摘　　要：采用Hyper Xtrude软件,对170 mm×4 mm的AZ31镁合金板材的连续挤压成形过程进行数值模拟,对单杆分流焊合模具结构进行了优化,并选取优化的模具结构进行连续挤压实验,得到了表面质量良好的AZ31镁合金板材。对AZ31镁合金板材进行了微观组织观察,结果表明:在截面上的微观组织分布不均,焊合区表面出现细晶带,在板材中间和边部位置出现大量孪晶,这是由于扩展成形过程中,板材截面的温度和变形程度不同所致。对板材力学性能进行了检测,得到纵向抗拉强度达到200. 4 MPa,伸长率为20. 8%,横向强度(焊缝强度)为170. 6 MPa,伸长率为7. 1%;板材纵向断口形貌表现为韧性断裂为主的断裂机制,而横向和45°方向主要表现为脆性断裂。The continuous extrusion process of AZ31 magnesium alloy sheet( 170 mm × 4 mm) was simulated by finite element software Hyper Xtrude,and the single rod split welding die structure was optimized. Then,the continuous extrusion experiments were conducted by the optimized die structure,and the AZ31 magnesium alloy sheet with good surface quality was obtained. Furthermore,the microstructure of AZ31 magnesium alloy sheet was observed. The results show that the grain size is unevenly distributed on the cross section,the fine grain belt appears on the surface of weld zone,and a large number of twins are found in the middle and edge areas of sheet. This is due to the different temperatures and deformation degrees on the cross section of sheet during the extending forming process. Finally,the mechanical properties were tested. It is found that the longitudinal tensile strength reaches 200. 4 MPa,and the elongation is 20. 8%. However the transverse strength( weld strength) is 170. 6 MPa,and the elongation is 7. 1%. Thus,from the fracture morphologies,the fracture mechanism of the longitudinal sample is dominated by the ductile fracture,but that of the transverse and 45° direction samples are mainly brittle fracture.

关 键 词：连续挤压 AZ31镁合金板材 微观组织 力学性能 断裂机制 

分 类 号：TG379[金属学及工艺—金属压力加工]