MICROSTRUCTURES AND MECHANICAL PROPERTIES OF BANDED TEXTURES OF FRICTION STIR WELDED 7075-T6 ALUMINUM ALLOY
KANG Ju1), LUAN Guohong1), FU Ruidong2)
1) Beijing Aeronautical Manufacturing Technology Research Institute, China Friction Stir Welding Center, Beijing 100024
2) Yanshan University, College of Materials Science and Engineering, Qinhuangdao 066004
Cite this article:
KANG Ju LUAN Guohong FU Ruidong. MICROSTRUCTURES AND MECHANICAL PROPERTIES OF BANDED TEXTURES OF FRICTION STIR WELDED 7075-T6 ALUMINUM ALLOY. Acta Metall Sin, 2011, 47(2): 224-230.
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.
