7075-T6铝合金搅拌摩擦焊焊缝表面带状纹理的组织与性能

来源期刊：金属学报2011年第2期

论文作者：康举 栾国红 付瑞东

文章页码：224 - 230

关键词：7075铝合金； 搅拌摩擦焊 (FSW)； 带状纹理； 微观组织； 力学性能

Key words：7075 aluminum alloy； friction stir welding (FSW)； banded textures； microstructure； mechanical property

摘    要：对1.6 mm厚7075-T6铝合金板进行了搅拌摩擦焊接(FSW),研究了焊缝表面带状纹理的组织与性能.研究表明,焊缝金相组织在轴肩作用区内存在明暗相间的弧纹,明弧纹对应带状纹理的波谷,暗弧纹对应波峰.SEM和TEM分析表明,与波谷处相比,波峰处为细晶区和第二相粒子的富集区,导致波谷处的硬度比波峰处低.

Abstract: Friction stir welding (FSW) is a ideal method for joining light metal materials, especially for AA2000 and AA7000 series aluminum alloys.In the welding field,many aspects of FSW have been studied quite extensively and comprehensively.However,the origin of the banded texture is still a subject of current research.One of the phenomena that strike researchers today is the occurrence of banded texture on the top surface in FSW joints.Furthermore,many waves also emerged in shoulder affected zone (SAZ) after a joint being polished and etched.The correlation between the banded textures and the waves is not clear.In this paper,1.6 mm thick 7075-T6 aluminum alloy sheets were friction stir welded,microstructures and hardness profile of banded textures on the top surface of the joint were investigated.The results of metallographic observation showed that alternately light and dark waves presented in SAZ,the light waves coincided with valleys of the banded textures,whereas the dark waves coincided with peaks.SEM and TEM analyses revealed that compared with the valleys, the peaks were characterized by more secondary phase particles and small grains,resulting in higher hardness at the peaks.