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利用透射电镜研究铝合金7050搅拌摩擦焊后各区微观结构演变。结果表明:热影响区位错开始滑移;热-力影响区位错发生交滑移或攀移,位错密度降低;焊核区晶内有少量位错。热影响区强化相严重粗化,热-力影响区强化相先固溶后重新析出,在晶内均匀分布,位错线成为强化相优先析出的核心;焊核区母材中固有的高温稳定相以及破碎的基体材料颗粒成为强化相优先析出的核心,强化相数量很少。
Transmission electron microscopy was used to study the microstructure evolution of the 7050 aluminum alloy after friction stir welding. The results show that the dislocation starts to slip in the HAZ, and the dislocation or climb of dislocation occurs in the thermal-force-affected zone. The dislocation density decreases. There are a few dislocations in the nucleus of the weld zone. In the heat affected zone (HAZ), the strengthening phase is coarsened intensively, and the strengthening phase in the heat-force influencing zone re-precipitates after solid solution and is uniformly distributed in the crystal. The dislocation line becomes the core of preferential precipitation of strengthening phase. The inherent high temperature stability Phase and broken matrix particles become preferential precipitation of reinforcing phase core, the number of strengthening phase is small.