超声深滚处理高强铝合金超声波焊层组织和织构研究

采用超声波金属焊接技术对2A12-T3和2A11-O铝合金进行了焊接,然后对焊层进行了超声深滚处理。通过扫描电镜、电子背散射衍射和透射电镜分析了超声深滚处理前后超声波焊层的宏观形貌和微观组织。扫描电镜和透射电镜分析表明,超声深滚处理能够有效去除超声波焊层表面的焊接压痕,降低表面粗糙度,使焊接界面的组织更加均匀。电子背散射衍射分析表明,超声深滚处理后焊层组织发生再结晶,形成再结晶织构和形变诱导晶粒长大,有助于消除焊接界面的焊接残余应力。因此,超声深滚处理有助于改善铝合金超声波焊层的组织和性能。

Microstructure and Texture of High Strength Aluminum Alloy Ultrasonic Welding Layer after Ultrasonic Deep Rolling

2A12-T3 and 2A11-O aluminum alloy were welded by ultrasonic welding (USW), and then ultrasonic deep rolling (UDR) treating was performed on the welded layer. Macromorphology and microstructure of the USW layers before and after UDR were investigated by scanning electron microscope (SEM), electron backscatter diffraction (EBSD) and transmission electron microscope (TEM). Results show that UDR can eliminate the surface welded indents, decrease surface roughness and make microstructure more homogenous at the welded interface. Recrystallization occurs in the USW layer after UDR to form recrystallization texture and strain-induced grain growth, which could reduce welding residual stress at the welded interface. Therefore, UDR is favorable to improve microstructure and properties of the USW layer.