铝镁合金填充式搅拌摩擦点焊接头的显微组织及力学性能

Microstructure and Mechanical Property of Refill Friction Stir Spot Welded Joint of Al-Mg Alloy

对2.0mm厚的5A06铝合金板进行不同工艺参数的填充式搅拌摩擦点焊,并对点焊接头进行了显微组织观察及剪切拉伸、十字拉伸试验。结果表明:接头可以分为焊核区、热机影响区、热影响区、压力影响区和母材区等部分,其显微组织主要为α-Al固溶体,并有金属间化合物β-Mg2Al3相等在基体上分布;随着焊接时间延长和焊接旋转速度的增大,点焊接头的剪切拉伸性能和十字拉伸性能呈现先快速增加后缓慢下降的趋势;当焊接旋转速度为2 000r·min-1,焊接时间为3.5s时,点焊接头最大剪切拉伸载荷可达8 194N,最大十字拉伸载荷可达3 565N。

Abstract： 5A06 Al aluminium alloy sheets in thickness of 2. 0 mm was welded by retlIl trmuon sur ,spur welding （FSPW）. The microstructure, tensile-shear strength and cross tension strength of the joint were tested. Results indicate that the joint can be divided in nugget zone, thermo-mechanically affected zone, thermal affected zone, pressure affected zone and the base material, respectively. The microstructure was mainly a-A1 solid solution, and α-Mg2Al3 intermetallic phase distributed in the matrix. With the welding time increased, the tensile-shear strength and cross-tension strength of the FSPW joints rapid increased at first and then slowly declined. When the rotational speed was 2 000 r · min 1 and the welding time was 3.5 s, the highest tensile shear load reached 8 194 N, and the highest cross-tension load reached 3 656 N.