Al-Zn-Mg合金焊接接头力学性能与微观组织演变的关系  

The relationship between the mechanical properties and microstructure changes of welded Al-Zn-Mg alloy joints

作　　者：秦芳[1] 孟立春[2] 杨修波[1] 刘聪[1] 陈江华[1] 刘春辉[1] 刘吉梓[1] 

机构地区：[1]湖南大学材料科学与工程学院,长沙410082 [2]南车青岛四方机车车辆股份有限公司,山东青岛266111

出　　处：《功能材料》2016年第3期237-242,共6页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(51301064;51171063)

摘　　要：Al-Zn-Mg合金焊接结构件是制造高速列车等重要轻量化交通工具的重要材料组件,而焊接接头的质量是决定整体部件性能的关键因素。通过性能测试和微观结构表征对高速列车上的典型焊接接头进行了深入的研究。结果表明,当不同的母材焊在一起时,由于原始组织结构的差异,焊接接头两侧热影响区的性能和组织演变规律将显著不同;而且其性能与组织结构也与焊接工艺紧密相关。Al-Zn-Mg alloy parts joined by metal inert-gas welding(MIG)are widely applied in high-speed trains as important structural components.In the present study,the joints of a T4-treated Al-Zn-Mg alloy plate with a T5-treated extrusion profile fabricated by MIG welding were studied to reveal the relationship between mechanical properties and microstructure changes of the welded joints,by means of electron back-scattering diffraction(EBSD),transmission electron microscopy(TEM),Vickers hardness test and fatigue test.The results show that the impacts of the heat inputs,introduced during welding,on the T4-treated plate,are rather different from that on the T5-treated extrusion profile section:There is a softened zone in the later part,and the softened zones are widened with the increase of number of repair welding,and the precipitates in the heat-affected zones are changed significantly,whereas the hardness of the HAZ of the former part remains nearly the same.Furthermore,fatigue life expectancy of the welded joints decreases slightly after repair welding.Pores and inclusions introduced by repair welding increase the uncertainty of fatigue performance.

关 键 词：焊接 铝合金 硬度 疲劳性能 析出相 

分 类 号：TG401[金属学及工艺—焊接] TG406