Effect of joining material direction on material flow, microstructure and mechanical properties of dissimilar AA2024/7075 joints fabricated by friction stir welding

作者：Shule Xing, Jing‐Wen Sun, Chenghang Zhang, Haoge Shou, Lei Jia, Na Lv · 发表于：Journal of Materials Research and Technology · 年份：2025 · DOI：10.1016/j.jmrt.2025.02.007 · 被引用次数：8 · 研究领域：Advanced Welding Techniques Analysis、Aluminum Alloys Composites Properties、Aluminum Alloy Microstructure Properties

In order to assess the effect of welding combinations types on material flow behavior, microstructure and mechanical properties of dissimilar friction stir welded (FSW) joints and complement and improve our previous work. AA2024-T351 and AA7075-T651 sheets were welded by using three types of welding combinations (TD‖RD, RD‖45° and 45°‖TD, RD-rolling direction, TD-transverse direction and 45°–45° to the RD). The results indicate that different types of welding combinations influence material flow behavior in the nugget zone (NZ) during FSW, the welding combination of RD‖45° results in sufficient material flow compared to the TD‖RD and 45°‖TD joints. For the three joints, the second phases are broken into fine particles in the NZ towards AS (ANZ), and aggregates together in the NZ towards RS (RNZ) under the rotation and agitation of the stirring pin and the grain size in the NZ is decreased from the top to the bottom. Different welding combination types result in different types of shear textures in the NZ. High tensile strength of 436.4 MPa is obtained for the RD‖45°joint, while relatively low tensile strength is acquired as 376.43 MPa for the 45°‖TD joint. The fracture locations of the three joints correspond to the softening zone of the micro-hardness value.