7075铝合金与H68黄铜的搅拌摩擦焊组织分析

摘要

采用金相显微镜对7075铝合金与H68黄铜异种材料搅拌摩擦焊接头组织进行观察、采用X射线衍射仪（XRD）对焊接接头中相结构进行分析,并采用显微硬度计对焊接接头硬度分布进行测试.结果表明,搅拌针的旋转频率为1 100 r/min,焊接速度为80 mm/min时,焊接接头未形成金属间化合物,焊核区晶粒细化,且显微硬度值增加,为明显再结晶等轴晶;焊核区铝与铜以片层状及旋涡状很好的结合在一起.%Microstructures of friction stir welding joint of 7075 aluminum alloy and H68 brass were observed by using optical microscopy（OM）.The phase structure of the joint was determined by X-ray diffraction（XRD）.Meanwhile,the micro-hardness of the welding joint was determined by microhardness tester.The results show that good weld joint is obtained when rotating speed is 1100 r/min and the welding speed is 80mm/min.7075 aluminum alloy and H68 brass are interweaving each other with river pattern and vortexes shape,intermetallic compounds are not formed in the lap joint.The weld nugget zone is mainly composed of recrystallization equiaxed grain.Meanwhile,the grain in nugget zone is refined and the micro-hardness is increased obviously.