LF21铝合金薄板搅拌摩擦焊组织与性能

采用搅拌摩擦焊方法对厚度为1.4 mm的LF21铝合金薄板进行单道对接焊实验。实验结果表明:在旋转速度为1 500 r/min,焊接速度为100~180 mm/min时,均可获得较好的焊接性能,焊缝的抗拉强度在125~134 MPa之间,焊接强度系数为基材强度的78%~83%,说明该铝合金薄板采用搅拌摩擦焊方法的焊接适应性好。硬度测试结果表明焊缝发生了软化,其软化区宽度约为25 mm。在焊接热循环的作用下,锰在焊缝区沿轧制方向析出并聚集成较粗大的脆性MnAl6化合物,降低了焊缝的抗拉强度。

Microstructure and property of friction stir welded LF21 aluminum sheet

Tests about friction stir butt-welds of LF21 aluminum sheet with 1.4 mm in thickness were made in a single pass.The experimental results show that when rotating speed is 1 500 r/min and welding speed is 100?180 mm/min,the good welds can be achieved.The tensile strength of welds is 125?134 MPa,which is between 78% and 83% of that of base metal.It shows that the welding adaptability of LF21 aluminum alloy is good.The micro-hardness result shows that the weld is softened,and the soften zone of weld is about 25 mm in width.The brittle MnAl6 compounds are precipitated along the rolling direction with the heat of welding,so the tensile strength of weld decreases.