Similar and dissimilar joining of AA6061-T6 and copper by single and multi-spot friction stirring
Similar and dissimilar joining of AA6061-T6 and copper by single and multi-spot friction stirring
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DOI：
10.1016/j.jmatprotec.2017.07.029
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发表时间：
2017-12
影响因子：
6.3
通讯作者：
A. Garg;A. Bhattacharya
中科院分区：
文献类型：
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作者：
A. Garg;A. Bhattacharya
采用无钉工具对AA 6061-T6铝合金与铜进行了单点和多点同异种搅拌摩擦点焊，研究了接头搭接剪切、横向抗拉强度的变化规律。建立了考虑搅拌区、热机械影响区、母材、肩部穿透和飞边区域的搭接剪切和横向拉伸加载条件的有限元模型。对于类似的FSSW接头，在搭接剪切试验中主要观察到从接头周边破坏，而在十字拉伸试验中观察到塞状和界面断裂。有限元结果预测最大应力和应变附近的这些地区。在异种接头中，大多数情况下从接头界面观察到板的失效和分离。在不同的接头中观察到金属间化合物的形成，其最大厚度靠近接头周边。由于动态再结晶，与基体金属相比，在搅拌区观察到显著量的晶粒细化。对失效表面的观察表明，在相似的接头中存在大量的韧窝，在不同的接头中存在微裂纹和断裂。
Similar and dissimilar friction stir spot welding (FSSW) between AA6061-T6 aluminum alloy and copper with single and multi-spots are prepared with pinless tool and variation of joint lap shear, cross tensile strength are investigated and presented. Finite element models for lap shear and cross tensile loading conditions are created considering the stir zone, thermo-mechanically affected zone, base metal, shoulder penetration and flash region. For similar FSSW joints, failure from joint circumference is mostly observed under lap shear test whereas plug type and interface fracture is observed in cross tensile test. Finite element results predicted maximum stress and strain near these regions. In dissimilar joints failure and separation of the sheets are mostly observed from the joint interface. Formation of intermetallic compound is observed in dissimilar joints having maximum thickness near the joint periphery. Significant amount of grain refinement as compared to the base metal is observed in stir zones due to the dynamic recrystallization. Observation of failure surfaces showed presence of numerous dimples all thought out the surface in similar joints and presence of micro-cracks, rupture in dissimilar joint.