Friction stir welding was invented at Welding institute, United Kingdom in the year 1991 and has ever since been proved to be one of the best solid state joining methods for materials such as aluminium and magnesium. Some of the aluminium alloys which are not able to weld (Al-Cu, Al-Zn-Mg alloy) by fusion welding techniques, which produce defects and reduce the mechanical properties on the weld nugget could be welded using friction stir welding (FSW) successfully with excellent joint efficiencies. However effect of the process parameters on the properties of weldment have not been investigated fully. In this study, 5mm thick plates of aluminium alloys AA2024 (4.4%Cu, 0.6%Mn, 1.6%Mg) and AA7075 (2.5%Mg, 1.4%Cu, 0.2%Cr, 5.6%Zn) is selected for investigation. The FSW welding process was conducted on varying the welding process parameters such as tool rotation speed (RPM), welding speed (mm/min) and tool pin profile by keeping downward force (kN) constant. The properties such as defects, macro and microstructure, micro hardness, tensile and bend behavior on welded plates were studied. Sixteen sets of butt welds were produced using straight and tapered cylindrical with left hand threaded FSW tool pins. It has been found out that defect free weld could be produced with the help of tapered cylindrical with left hand threaded tool pin with tool rotation speed of 600 RPM, welding speed of 30 mm/min and downward force of 2.5 kN
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机译：摩擦搅拌焊接在1991年的英国焊接研究所发明，以来已被证明是铝和镁等材料的最佳固态联合方法之一。通过熔接焊接技术焊接（Al-Cu，Al-Zn-Mg合金）的一些铝合金，可以使用摩擦搅拌焊接（FSW）焊接焊接和减少焊扣上的机械性能成功具有出色的联合效率。然而，工艺参数对焊接性能的影响尚未完全研究。在该研究中，选择5mm厚的铝合金AA2024（4.4％Cu，0.6％Mn，1.6％Mg）和Aa7075（2.5％Mg，1.4％Cu，0.2％Cr，5.6％Zn）进行研究。通过保持向下的力（kN）恒定，在改变焊接工艺参数，例如刀具转速（RPM），焊接速度（MM / MIN）和工具引脚轮廓的焊接工艺参数上进行FSW焊接工艺。研究了焊接板上的缺陷，宏观和微观结构，微硬度，拉伸和弯曲行为的性质。使用直的圆柱形和左手螺纹FSW工具销产生十六套对接焊接。已经发现，可以通过左手螺纹工具引脚的锥形圆柱形的帮助，使用刀具转速为600 rpm，焊接速度为30mm / min 2.5 kn的焊接速度和2.5kn的向下
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