Yang Haifeng, Zhao Hongyun, Xu Xinxin, Zhou Li, Zhao Huihui, Liu Huijie
State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China.
Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology, Weihai 264209, China.
Materials (Basel). 2021 Apr 13;14(8):1938. doi: 10.3390/ma14081938.
In this study, 2A14-T4 Al-alloy T-joints were prepared via stationary shoulder friction stir welding (SSFSW) technology where the stirring pin's rotation speed was set as different values. In combination with the numerical simulation results, the macro-forming, microstructure, and mechanical properties of the joints under different welding conditions were analyzed. The results show that the thermal cycle curves in the SSFSW process are featured by a steep climb and slow decreasing variation trends. As the stirring pin's rotation speed increased, the grooves on the weld surface became more obvious. The base and rib plates exhibit W- or N-shaped hardness distribution patterns. The hardness of the weld nugget zone (WNZ) was high but was lower than that of the base material. The second weld's annealing effect contributed to the precipitation and coarsening of the precipitated phase in the first weld nugget zone (WNZ1). The hardness of the heat affect zone (HAZ) in the vicinity of the thermo-mechanically affected zone (TMAZ) dropped to the minimum. As the stirring pin's rotation speed increased, the tensile strengths of the base and rib plates first increased and then dropped. The base and rib plates exhibited ductile and brittle/ductile fracture patterns, respectively.
在本研究中，采用搅拌针转速设定为不同值的搅拌摩擦焊（SSFSW）技术制备了2A14-T4铝合金T型接头。结合数值模拟结果，分析了不同焊接条件下接头的宏观成型、微观组织和力学性能。结果表明，搅拌摩擦焊过程中的热循环曲线具有急剧上升和缓慢下降的变化趋势。随着搅拌针转速的增加，焊缝表面的沟槽变得更加明显。母材和肋板呈现W形或N形硬度分布模式。焊核区（WNZ）的硬度较高，但低于母材。第二次焊接的退火作用导致第一次焊核区（WNZ1）析出相的析出和粗化。热机械影响区（TMAZ）附近的热影响区（HAZ）硬度降至最低。随着搅拌针转速的增加，母材和肋板的抗拉强度先增加后下降。母材和肋板分别呈现韧性和脆性/韧性断裂模式。
