5052-H112铝合金搅拌摩擦点焊剪切拉伸强度和失效模式

Shear tensile strength and failure modes of friction stir spot welded 5052-H112 aluminum alloy

采用自行设计的圆锥凹面搅拌头对厚度为1 mm的5052-H112铝合金薄板进行搅拌摩擦点焊,研究了焊接工艺参数(搅拌头旋转速度、轴肩压入深度)对接头剪切拉伸载荷及失效模式的影响。结果表明:当轴肩压入深度一定时,焊点的剪切拉伸载荷随旋转速度的增加而减小;当旋转速度一定时,焊点的剪切拉伸载荷随着轴肩压入深度的增加先增加后减小。当旋转速度为1 008 r/min,轴肩压入深度为0.2 mm时,点焊接头的剪切拉伸载荷最大值为4.55 kN。点焊接头的失效模式十分复杂,其主要受搅拌工具旋转速度的影响。在不同的旋转速度下点焊接头呈现不同的失效模式。

A 5052-H112 aluminum alloy sheet with a thickness 1mm was friction stir spot welded（FSSW） using a self-designed conical concave tool.The effects of welding parameters（such as tool rotational speed,and shoulder plunge depth） on the shear tensile strength and failure modes of the joints was investigated.It is shown that the shear tensile load decreases with increasing rotational speed for a given shoulder plunge depth.Meanwhile the shear tensile load firstly increases then decreases when the shoulder plunge depth increases for a given rotational speed.The value of shear tensile load for the FSSW joints can reach the maximum of 4.55 kN for the rotational speed of 1 008 r/min and the shoulder plunge depth of 0.2 mm.The failure modes of friction stir spot welds are quite complex and strongly dependent on tool rotational speed.This indicates different failure modes for different tool rotational speeds.