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通过对镁合金AZ31进行搅拌摩擦焊获得了成型良好的焊缝,采用金相显微镜对焊缝组织进行了分析,并采用透射电镜和X射线能谱仪对晶粒形貌和晶界析出的第二相进行了观测分析。结果表明,镁合金搅拌摩擦焊可以获得组织致密的焊缝,焊缝区域根据组织特点可以分为焊核区、热机影响区和热影响区;焊核区“洋葱环”之间呈现层片状结构,晶界强化相数量减少且尺寸变小;热机影响区在前进侧和焊核区有明显的分界,晶粒呈细长条状,后退侧和焊核区分界相对不明显,晶粒变形较小;热影响区在前进侧较窄,组织与母材组织相比变化较小,而后退侧热影响区较宽,晶粒尺寸有所增长,这与搅拌摩擦过程中金属切削迁移的堆积过程有关。
Through the friction stir welding on the AZ31 magnesium alloy, a well-formed weld was obtained. The microstructure of the weld was analyzed by metallographic microscope. The microstructure of the weld was analyzed by transmission electron microscopy and X-ray energy dispersive spectroscopy Two phases were observed and analyzed. The results show that the microstructure of the welding seam can be divided into welding zone, heat affected zone and heat affected zone according to the microstructure characteristics of the friction stir welding of magnesium alloy. The weld zone between the “onion ring” Flake structure, the number of grain boundary strengthening phase decreases and the size becomes smaller; heat affected zone in the advancing side and the weld zone there is a clear boundary, the grain was slender strip, the back side and the nugget boundary is relatively clear, crystal The grain deformation is smaller; the heat affected zone is narrower on the advancing side, the change of microstructure is less than that of base metal, and the heat affected zone is wider and the grain size is increased, which is in agreement with the metal cutting and migration The accumulation process.