5083铝合金搅拌摩擦焊接头的显微组织与力学性能

Microstructure and Mechanical Prorerties of Friction Stir Welding Joints of 5083 Aluminium Alloy

对8 mm厚5083-H321铝合金板进行了搅拌摩擦焊接试验,研究了焊接工艺参数对搅拌摩擦焊接头显微组织和力学性能的影响。结果表明:该搅拌摩擦焊接头焊核区显微组织为细小的等轴晶组织,热机影响区为拉伸弯曲变形组织,热影响区非常窄,其晶粒尺寸与母材相当;综合接头表面形貌和拉伸性能得到较佳的搅拌摩擦焊接工艺参数为使用搅拌针为三棱形带螺纹、轴肩为内扣型的搅拌头,主轴转速为300 r·min^(-1),焊接速率为120 mm·min^(-1);在该工艺条件下接头表面成形良好,抗拉强度可达到母材的94.5%。

5083-H321 aluminium alloy plate with thickness of 8 mm were successfully welded by friction stir welding （FSW） method, and the effect of welding parameters on microstructure and mechanical properties of FSW joints were studied. The results show that microstructure of the nugget zone was fine equiaxial grain, microstructure of thermo mechanically affected zone （TMAZ） was stretch bending deformation structure, and the heat affected zone was very narrow and the grain size was similar to the base metal. The optimal FSW parameters according to the surface morphology and the tensile test results was using three prismatic threaded stir pin and inner button type shoulder, and with the rotating speed of 300 r ·min^-1 and welding speed of 120 mm ·min^-1. Under these conditions, the FSW joint surface was good, and the tensile strength could reach 94. 5% of that of the base metal.