连续挤压制备铝包镁复合棒材的组织与力学性能  

Microstructure and mechanical properties of Al clad Mg composite bars fabricated by continuous extrusion

作　　者：郭浩然 郭丽丽[1,2] 赵颖[1,2] 裴久杨[1,2] 伏洪旺 运新兵[1,2] GUO Haoran;GUO Lili;ZHAO Ying;PEI Jiuyang;FU Hongwang;YUN Xinbing(College of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,Liaoning,China;Engineering Research Center of Continuous Extrusion(Ministry of Education),Dalian Jiaotong University,Dalian 116028,Liaoning,China)

机构地区：[1]大连交通大学材料科学与工程学院,辽宁大连116028 [2]大连交通大学连续挤压教育部工程研究中心,辽宁大连116028

出　　处：《材料工程》2023年第7期197-205,共9页Journal of Materials Engineering

基　　金：辽宁省自然科学基金项目(2019-MS-035)。

摘　　要：在不同的加热温度下,采用不同尺寸的坯料并利用连续挤压工艺进行6063铝合金包AZ31镁合金复合材料的制备,获得尺寸为∅5 mm的复合棒材。通过扫描电镜(SEM)、金相显微镜以及万能拉伸试验机等分析手段对制备的复合棒材进行微观组织分析和力学性能测试。结果表明:连续挤压工艺可显著细化复合棒材镁芯的晶粒。坯料在室温挤压时,镁芯的平均晶粒尺寸为15.4μm,复合棒材的抗拉强度为141.4 MPa,伸长率为6.6%。加热温度升高至450℃时,镁芯晶粒开始长大,复合棒材的抗拉强度略有下降,伸长率提高到10%。随着镁芯直径增大,组织均匀性和晶粒细化效果提高,平均晶粒尺寸为12.8μm。在连续挤压过程中,铝镁之间发生相互扩散,产生硬度较高的铝镁结合层,结合层最大厚度为4.8μm。利用Deform有限元软件模拟连续挤压过程中的材料流动,得到了Al和Mg的温度与应变分布,有助于分析连续挤压过程中复合棒材的组织演变。6063 Al alloy clad AZ31 Mg alloy composite materials were fabricated by continuous extrusion under different heating temperatures with various billet diameters.The composite bars with the size of∅5 mm were obtained.The microstructure and mechanical properties of the composite bars were analyzed by means of scanning electron microscope(SEM),optical microscope and tensile tests.The results show that grains in Mg core of the composite bars can be significantly refined by continuous extrusion.The average grain size of Mg core is 15.4μm.The tensile strength of the composite material is 141.4 MPa and the elongation is 6.6%when the billets are extruded at room temperature.The average grain size of the Mg core increases with the heating temperature.In addition,the tensile strength of the composite material slightly decreases but the elongation is improved to 10%when the billets are extruded at the heating temperature of 450℃.Moreover,the microstructure shows more homogeneous and more refined grains by using a larger diameter of Mg core.The average grain size is refined to 12.8μm.The results of SEM observation show that the interdiffusion occurs between Al and Mg during continuous extrusion.The largest thickness of the diffusion layer is 4.8μm.The highest hardness is observed at the middle of the interface.At the same time,the material flow of Al-Mg during continuous extrusion is simulated by Deform finite element(FE)software.The temperature and strain distributions of Al and Mg are obtained by the FE simulation,which is helpful to understanding the microstructure evolution during continuous extrusion.

关 键 词：镁合金 铝合金 连续挤压 复合材料 

分 类 号：TG379[金属学及工艺—金属压力加工]