2195铝锂合金摩擦搅拌焊接头组织

发布时间：2018-11-09 18:22

【摘要】：采用圆柱形搅拌头和带螺纹搅拌头,制备2195-T8铝锂合金摩擦搅拌焊接头,研究搅拌头前进速度与旋转速度对接头孔洞缺陷的影响,分析接头的显微组织特征。结果表明:当圆柱形搅拌头旋转速度与前进速度比值不当时,在接头前进侧下部容易产生贯穿整个接头的隧道型缺陷(连续孔洞);采用带螺纹搅拌头可以消除接头的这种缺陷,有效提高接头抗拉强度。2195-T8铝锂合金基材中强化相包括T1相(Al_2CuLi)和θ′相(Al_2Cu);热机影响区所有θ′相及大部分T1相溶解;而焊核区T1相和θ′相均完全溶解,并在焊核区产生较多位错。热影响区和基材为沿轧制方向的板条状晶粒;热机影响区晶粒发生偏转和变形;焊核区晶粒均发生再结晶,但焊核区边缘近热机影响区再结晶晶粒尺寸较小,而中心焊核区再结晶晶粒长大。
[Abstract]:The 2195-T8 Al-Li alloy friction stir welding joints were prepared by using cylindrical and threaded stirring heads. The effects of the speed of the stirring head and the rotating speed on the hole defects of the joints were studied and the microstructure characteristics of the joints were analyzed. The results show that when the ratio of rotating speed to advancing velocity of cylindrical stirring head is not at the same time, tunneling defects (continuous holes) are easy to occur in the lower part of the forward side of the joint. This defect can be eliminated and tensile strength of the joint can be effectively improved by using a threaded mixing head. The strengthened phases in 2195-T8 Al-Li alloy substrate include T1 phase (Al_2CuLi) and 胃 'phase (Al_2Cu). All 胃 'phases and most T1 phases are dissolved in the affected zone, while the T1 phase and 胃' phase in the nugget zone are completely dissolved, and more dislocations occur in the nugget zone. The heat affected zone and the substrate are strip grains along the rolling direction, and the grains in the heat affected zone are deflected and deformed. Recrystallization occurs in the nugget zone, but the recrystallization grain size is smaller in the near thermal effect zone of the nugget zone, while the recrystallization grain grows in the central nugget zone.
【作者单位】：航天材料及工艺研究所;中南大学材料科学与工程学院;
【基金】：国家高技术研究发展计划资助项目(2013AA032401)~~
【分类号】：TG453.9;TG146.21

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