【摘要】 基于耦合欧拉-拉格朗日有限元法数值模拟了铝合金5052与高强钢DP590搅拌摩擦搭接过程中的温度场演变和材料流动行为。结果表明，有限元预测温度场和焊缝变形轮廓与实验测量结果吻合良好。当移动速度保持300 mm/min恒定不变时，随着转速由500 r/min增至1 000 r/min，搅拌区峰值温度位置由前进侧的轴肩后方的铝合金表面转移至搅拌针底部与钢搅拌区的界面，峰值温度由545℃增加至635℃；在焊接过程中，前进侧温度始终高于后退侧温度，与转速无关。采用示踪粒子法研究材料迁移轨迹，发现前进侧铝合金从更靠近搅拌针的内侧剪切层绕过搅拌针填埋在搅拌针前进侧后方，而后退侧铝合金主要迁移至搅拌针后退侧后方，迁移轨迹比较发散；搅拌针作用在铝/钢搭接面，驱使前进侧钢材料迁移至搅拌针后退侧后方，并在垂直方向上挤入上侧铝合金焊缝区。随着搅拌针转动，由前进侧迁移至后退侧的钢材料最终促使后退侧形成尺寸较大的钩状结构。相比于铝合金侧，转速的增加更为显著地加强了钢表面的材料流动。更多还原

【Abstract】 The heat transfer and material flow behavior during friction stir lap welding(FSLW) of Al alloy 5052 and high-strength steel DP590 were numerically simulated based on the coupled Euler-Lagrangian finite element method(CELFEM). The predicted results of the temperature histories and the deformation profile of the weld matched well with the experimental measurements. The simulation results show that when the welding speed is kept constant at 300 mm/min, as the rotation speed increases from 500 r/min to 1 000 r/min, the peak temperature position of the stirring zone is transferred from the Al alloy surface behind the shoulder on the advancing side(AS) to the bottom of the stirring pin, that is, the interface of the steel stirring zone. Meanwhile, the peak temperature increases from 545 °C to 635 °C during the welding process. Regardless of rotation speed, the temperature on the AS is always higher than that of the retreating side(RS). The material migration was studied by the tracer particle method. The Al alloy materials on the AS are eventually transferred to the rear region of the AS, bypassing the RS via the inner shear region, which is close to the stirring pin and shoulder root. The Al alloy materials on the RS were mainly migrated to the ipsilateral rear, and the migration trajectory is more divergent. The stirring pin acts on the Al/steel overlapping surface, driving the steel materials on the AS to move to the RS rear of the stirring pin and simultaneously extruding the steel materials into the Al weld area in the vertical direction. The steel material that migrates from the AS to the RS as the pin rotates eventually causes the RS to form a larger-sized hook-like structure. Compared with the Al alloy side, the increase in rotating speed more significantly enhances the material flow on the steel surface.更多还原