搅拌针形貌对2219铝合金搅拌摩擦焊接头性能的影响

Effect of Pin Morphology on the Performance of FSW Joint of 2219 Aluminum Alloy

2219铝合金以其优异的力学性能被广泛地应用于火箭燃料贮箱制造,搅拌摩擦焊作为2219铝合金焊接的主要工艺之一,搅拌针形貌对其接头的组织结构和力学性能有着直接影响。采用半螺纹-三弧面和全螺纹-三平面两种几何结构的搅拌针进行FSW焊接数值模拟,并对不同螺纹特征的全螺纹-三平面搅拌针作用下接头的横截面形貌和力学性能进行对比分析。结果表明,搅拌针几何结构对焊接温度场的影响较小,但对流动场和应变速度的影响较大,弧面特征对于材料的驱动作用强于平面特征,并且半螺纹-三弧面搅拌针与隧道孔缺陷的关联性更强。试验结果表明,全螺纹-三平面搅拌针对13 mm厚板FSW接头组织和性能的影响主要是热输入量和温度分布差异所导致的。

2219 aluminum alloy has been widely used in the manufacture of rocket fuel tanks due to its excellent mechanical properties.FSW is one of the main welding processes of 2219 aluminum alloy.The microstructure and mechanical properties of the joint are directly affected by the morphology of the pin.In order to reveal the effect of the morphology of the pin on the joint performance,the welding numerical analysis was carried out by using semi-helical tri-arcs and full-helical triplanes geometric structures,moreover,the mechanical properties of the joint under the welding of full-helical tri-planes pin with different thread characteristics were analyzed.The results showed that the effect of the pin geometry on the welding temperature field was slight,however,the flow field and strain rate were strong.Moreover,the connection between the semihelical tri-arcs and the tunnel hole defect was closer.The experimental results showed that the influence of the characteristics of full-helical tri-planes pin on the microstructure and properties of 13 mm FSW joint were mainly caused by the difference of heat input and temperature distribution.