7A52铝合金搅拌摩擦焊接头特征分析

通过7A52铝合金的搅拌摩擦焊试验,分析讨论了其焊接接头特征。试验中有目的地选择了几种不同的工艺规范进行研究。结果表明:焊接接头横截面宏观结构特征表现为焊核区的"洋葱环"和热-机械影响区的塑性流线变形,洋葱环的环间距随着距焊缝中心距离的增大而减小;表面的宏观结构特征表现为半圆环带,环间距与搅拌头旋转速度和焊接速度有关。此外,还讨论了搅拌头旋转速度和焊接速度对焊接接头力学性能影响。接头显微硬度的最低值出现在焊接热影响区而不在焊核区,主要是焊核区经过动态再结晶形成了细小的等轴晶所致。

Characteristic analysis for friction stir welding of 7A52 aluminum alloy

An extensive investigation was carried out on friction stir welding joint feature of the 7A52 aluminum alloy . With the purposeful selection of different welding parameters, macro - structural feature of different section was analyzed. The experiment result shows that the spacing of onion rings, which is the most prominent features of most friction stir welds, decreases with the distance of onion ring to centerline increasing . On surface, the differences in the average semicircular spacing can be quite large at low rpm values while differ very little at high rpm (revolutions per minute) and the higher welding speed produces the wider ring spacing. Furthermore, the micro - hardness and intensity of weld is related to rpm and traverse speed. The minimal micro - hardness locates on the heating affected zone while doesn' t locate on the weld nugget, which primarily results from fine grain equiaxed structure developed by dynamic recrystallization.