摘要
Dissimilar friction stir welding between AZ31-O Mg and 6061-T6 Al alloys was investigated. 3 mm thick plates of aluminum and magnesium were used. Friction stir welding operations were performed at different rotation and travel speeds. The rotation speeds varied from 600 to 1400 r/min, and the travel speed varied from 20 to 60 mm/min. Defect-free weld was obtained with a rotation speed of 1000 r/min and travel speed of 40 mm/min. Metallographic studies showed that the grain size in the stir zone is much finer than that in the base metals. Complex flow pattern was formed in the stir zone. Microhardness measurement revealed an uneven distribution in the stir zone. Tensile test results indicated that the tensile strength of the welded specimen is about 76% of AZ31 Mg alloy and 60% of the 6061 Al alloy in tensile strength. SEM fracture surface image of the welded specimen indicated that the welded specimen failed through brittle-mode fracture.
对3 mum厚的AZ31-O镁合金板和6061-T6铝合金板进行异种材料搅拌摩擦焊.实验中搅拌针的旋转速度为600～1400 r/min,前进速度为20～60 mm/min.结果表明,在旋转速度1000 r/min、前进速度40 mm/min的工艺条件下,可以获得无缺陷的焊接接头.组织观察发现搅拌区的晶粒尺寸要比基材区的明显小很多.在搅拌区形成了复杂的金属流动.显微硬度测试表明搅拌区的硬度分别是不均匀的.拉伸实验结果表明,接头的拉伸强度约为基材AZ31镁合金的76％,或6061铝合金的60％.接头拉伸断口SEM形貌观察表明为脆性断裂.
