Abstract: The ER5356 welded wire was welded under the TIG welding to 5 mm thick 7075-T6 super hard aluminum. The performance and microstructure of the welded joints obtained under different welding processes were analyzed, and the best welding parameters were determined. After solid solution treatment for the specimens, four solid solution temperature and three solid solution time were selected for the experiment. The change law of microstructure and properties of welded joints under different solid solution parameters was studied through macro morphology and metallographic observation, scanning electron microscope, X ray diffraction analysis, tensile test and hardness measurement. The results show that the best welding current is 110 A determined by welding technology, solid solution treatment temperature is 480 ℃, solid solution time is 45 min. At this time, the microstructure of welded joints is improved, and the mechanical properties of the welded joints are better. That is, the size of the grain structure is homogeneous, and the precipitates are dispersed in the matrix and grain boundaries. Thus, more elements are dissolved into the matrix and the grain boundary.

Key words: 7075 super-hard alloy, Tungsten grade argon arc welding, Solution treatment, Micro-structure, Mechanical property

摘要： 采用ER5356焊丝在TIG焊下对5 mm厚的7075 -T6超硬铝进行焊接，对在不同焊接工艺下获得的焊接接头进行性能检测和组织分析，确定最优的焊接工艺参数。然后对试件进行固溶处理，选取4个固溶温度、3个固溶时间进行试验，通过宏观形貌和金相观察、扫描电镜观察、X射线衍射分析、拉伸实验和硬度测量，研究不同固溶参数下焊接接头组织及性能的变化规律。结果表明，通过焊接工艺性分析确定最佳焊接电流为110 A，焊后固溶处理最佳参数匹配为焊接电流110 A、固溶温度480 ℃、固溶时间45 min，得到的焊接接头显微组织得以改善、组织力学性能较好，即晶粒组织大小均匀，析出相弥散分布在基体和晶界中，从而使更多的元素溶入基体和晶界。

关键词: 7075超硬铝, 钨级氩弧焊, 固溶处理, 显微组织, 力学性能