连续变断面循环挤压镁合金微观组织与力学性能研究
发布时间：2018-08-13 12:40
【摘要】：本文采用连续变断面循环挤压(Continuous variable cross-section recycled extrusion,CVCE)技术对挤压态AZ31镁合金进行挤压变形,研究了CVCE技术对AZ31镁合金组织及力学性能的影响。利用光学显微镜、XRD等技术对AZ31镁合金的晶粒尺寸、晶粒取向等微观结构进行表征,分别沿水平方向和轴向进行显微硬度和室温拉伸性能测试。并采用DOFORM有限元软件对AZ31CVCE工艺进行数值模拟,取得的主要研究结果有:通过数值模拟和挤压实验研究确定了AZ31镁合金CVCE挤压最佳工艺参数。变形速度为2 mm/s、第1到3循环的挤压温度分别为350℃、330℃和300℃,对应循环的保温时间分别为13 min、11 min和10 min。随着变形循环的增加,晶粒逐渐细化且组织均匀性改善,但随着循环数的增加,晶粒发生异常长大现象。晶粒取向发生了定向改变,由母材各个面都有较强织构转变为只有基面织构较强,而且织构方向平行于AZ31镁合金晶粒的c轴。在水平方向上,变形后的试样的抗拉强度均得到提高,但延伸率有所降低;在轴向上,变形后抗拉强度和延伸率均得到了提高。采用DEFORM软件对较优的变形工艺参数进行温度场、应力场、应变场和金属流动方向的模拟,变形过程中发生变形能和热能之间转换,随着变形循环的增加应变量不断累积,变形循环为5时,试样中间部位的累积应变量可达到4,且分布较为均匀,并且模拟的应变值与公式计算相一致。
[Abstract]:In this paper, the extrusion deformation of extruded AZ31 magnesium alloy was carried out by continuous variable section cyclic extrusion (Continuous variable cross-section recycled) technique. The effect of CVCE technology on the microstructure and mechanical properties of AZ31 magnesium alloy was studied. The grain size and orientation of AZ31 magnesium alloy were characterized by optical microscope. The microhardness and tensile properties at room temperature were measured along the horizontal and axial directions, respectively. The DOFORM finite element software is used to simulate the AZ31CVCE process. The main results are as follows: through numerical simulation and extrusion experiment, the best process parameters of CVCE extrusion for AZ31 magnesium alloy are determined. The extrusion temperature of the first to third cycles is 350 鈩，
本文编号：2181023
[Abstract]:In this paper, the extrusion deformation of extruded AZ31 magnesium alloy was carried out by continuous variable section cyclic extrusion (Continuous variable cross-section recycled) technique. The effect of CVCE technology on the microstructure and mechanical properties of AZ31 magnesium alloy was studied. The grain size and orientation of AZ31 magnesium alloy were characterized by optical microscope. The microhardness and tensile properties at room temperature were measured along the horizontal and axial directions, respectively. The DOFORM finite element software is used to simulate the AZ31CVCE process. The main results are as follows: through numerical simulation and extrusion experiment, the best process parameters of CVCE extrusion for AZ31 magnesium alloy are determined. The extrusion temperature of the first to third cycles is 350 鈩，
本文编号：2181023
本文链接：https://www.wllwen.com/kejilunwen/jiagonggongyi/2181023.html
