Al-Mg合金填充式搅拌摩擦点焊性能

为了确定Al-Mg铝合金填充式搅拌摩擦点焊性能,以Al-Mg铝合金中2 mm的5A06为研究对象,对填充式搅拌摩擦点焊接头进行了剪切拉伸、十字形拉伸、显微组织和疲劳性能等测试,并建立了焊点组织区模型.结果表明,接头显微组织可以分为焊核区、热影响区、热力影响区和母材区部分;旋转频率为2000 r/min时,剪切载荷均值7865 MPa,十字形拉伸载荷均值3480 N;通过SEM和OM分析,点焊接头疲劳裂纹均起始于上下板结合面的焊点边缘,该区域的环沟槽、孔洞及包铝层等缺陷和应力集中是造成疲劳破坏的主要原因.

Properties of Al-Mg alloys joints welded by refill friction stir spot weldeing process

In order to determine the properties of refill friction stir spot welded (RFSSW) Al-Mg alloys joints,tests on tensile/shear strength,cross-tension strength,microstructure and fatigue properties of refill friction stir spot welded joints were conducted with 2 mm-thickness 5A06 aluminum alloy as research subject,and microstructure model of RFSSW joint was established as well. Experimental results indicated that the microstructure of the joints could be divided into nugget zone,heat affected zone,thermo-mechanically affected zone and base material, respectively. When the rotational speed was 2 000 rpm,the tensile/shear strength was able to reach 8 194 N,and the highest cross-tension strength was 3565N. SEM and OM analysis showed that fatigue cracks initiated from weld edge on the joining surface of the upper and lower plates,and defects including ring groove, cavity,aluminum clad in this area,as well as stress concentration were the main causes for fatigue damage.