铝合金7050搅拌摩擦焊接头微观结构演化
Microstructure Evolution of Joint of Aluminum Alloy 7050 by FSW
金玉花， 王希靖， 李常锋， 张昌青
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作者单位：兰州理工大学 甘肃省有色金属新材料省部共建国家重点试验室，甘肃 兰州 730050
中文关键字：搅拌摩擦焊； 铝合金； 位错； 强化相； 析出
英文关键字：friction stir welding; aluminium alloy; dislocation; strength-phase; precipitation
中文摘要：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。
英文摘要：The microstructure evolution of aluminum alloy 7050 in different zone after friction stir welded(FSW) was investigated using TEM. The results show that dislocation starts to glide in HAZ. The dislocation density decreases because of dislocation across glide or climbing in the thermo-mechanically affected zone (TMAZ). The dislocation density is low in the nugget zone. At the same time, the strength-phase is coarse in HAZ, the strength-phases dissolve into base material firstly and then precipitates from the solid solution along the dislocation in TMAZ. These strength-phases distribute homogeneously in the grain interior, and the strength-phases precipitate around the heterogeneous particles such as the stable phases in matrix material at high temperature and the broken matrix material particle in the nugget.