Different morphology and thinning cases of the weld zone of a 7022 aluminum alloy in friction stir welding were analyzed. Metal plastic flow processes in the contact zone for an aerospace friction stir-joint 7022 aluminum alloy were evaluated. The cross section of the contact zon was analyzed by metallographic and tool microscopes. Then, the plastic flow law of the contact zone was established. Theoretical analysis confirmed the validity of the metal plastic flow law and corresponding thinning model of the weld zone. The thinning model for filling due to indirect extrusion–vortex flow can adequately characterize the plastic flow of metals and formation process of thinning in the weld zone.

分析了7022铝合金搅拌摩擦焊时不同形貌和变薄情况。评估了航空摩擦搅拌接头7022铝合金在接触区中的金属塑性流动过程。接触区的横截面通过金相和工具显微镜进行分析。然后，建立了接触区的塑性流动规律。理论分析证实了金属塑性流动规律和相应的焊缝薄化模型的有效性。由于间接挤压-涡流而产生的填充稀化模型可以充分表征金属的塑性流动和焊接区域中稀化的形成过程。