Li Qi, Zhang Chenghang, Sun Jianhong, Shou Haoge
College of Intelligent Manufacturing, Huanghuai University, Zhumadian 463000, China.
Ningbo Institute of Technology, Beihang University, Ningbo 315800, China.
Materials (Basel). 2025 Jan 14;18(2):340. doi: 10.3390/ma18020340.
Friction-stir-welded dissimilar AA2024/AA7075 joints have an apparent influence on grain and texture development at the weld interface due to differences in physical and chemical properties between the two aluminum alloys. In this work, the effect of tool shoulder profile on grain structure and texture evolution in the center interface zone (CIZ) and bottom interface zone (BIZ) of dissimilar AA2024/AA7075 joints were quantitatively studied by electron back-scattering diffraction (EBSD). The results indicate that abundant fine and coarse equiaxial grains are produced in the CIZ and BIZ of the joints produced with a concentric circle shoulder (CCS) and three-helix shoulder (THS), and the average grain size of the BIZ is lower than that of the CIZ for the same CCS or THS joint. A higher degree of recrystallization occurs in the CIZ of the joint with a CCS than that of the joint with a THS, while a similar degree of recrystallization is presented in the BIZ of the two joints. For the distribution of local misorientation angle between the two sides of the interface in the same CCS or THS joint, the CIZ manifests relatively uniform behavior, while the BIZ presents the characteristics of uneven distribution. Tool shoulder profile has a significant impact on the texture components at the weld interface, which results in different types of shear textures generated in the CIZ and BIZ of the two joints. It is beneficial to make out the microstructural evolution mechanism at the weld interface in dissimilar FSW joints for engineering applications in this study.
搅拌摩擦焊的异种AA2024/AA7075接头对焊接界面处的晶粒和织构发展有显著影响，这是由于两种铝合金在物理和化学性质上存在差异。在本研究中，通过电子背散射衍射（EBSD）定量研究了工具肩部轮廓对异种AA2024/AA7075接头中心界面区（CIZ）和底部界面区（BIZ）的晶粒结构和织构演变的影响。结果表明，采用同心圆肩部（CCS）和三螺旋肩部（THS）制造的接头的CIZ和BIZ中产生了大量的细等轴晶和粗等轴晶，对于相同的CCS或THS接头，BIZ的平均晶粒尺寸低于CIZ。采用CCS的接头的CIZ中的再结晶程度高于采用THS的接头，而两个接头的BIZ中的再结晶程度相似。对于同一CCS或THS接头中界面两侧局部取向差角的分布，CIZ表现出相对均匀的行为，而BIZ呈现出分布不均匀的特征。工具肩部轮廓对焊接界面处的织构成分有显著影响，这导致两个接头的CIZ和BIZ中产生不同类型的剪切织构。本研究对于了解异种搅拌摩擦焊接头焊接界面的微观组织演变机制以用于工程应用是有益的。
