Abstract In this work, thin aluminum alloy sheets with thickness of 0.8 mm were friction stir lap welded using small shoulder plunge depths of 0 and 0.1 mm. The joint formation, microstructure and mechanical properties were investigated. Results show that voids appear inside the stir zone when the small plunge depth of 0 mm is used because the tool shoulder cannot exert a good material-collecting effect at such low plunge depth. A plunge depth of 0.1 mm causes tight contact between the shoulder and the material and thus results in good material-collecting effect, which is helpful to eliminate the void. Sound joints are attained at a wide range of welding parameters when using the shoulder plunge depth of 0.1 mm. No crack is observed inside the bonding ligament. The joints own higher failure loads when the retreating side (RS) of the joint bares the main load during the lap shear tests. The shear failure load first increases and then decreases with increasing the rotating and welding speeds, and the maximum failure load of 6419 N is obtained at 600 rpm and 150 mm/min. The hardness of the joint presents a “W” morphology and the minimum hardness is obtained at the heat affected zone. The joints present tensile fracture and shear fracture when the advancing side and RS bare the main loads, respectively.

中文翻译：

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搅拌摩擦搭接焊薄铝合金板

摘要 在这项工作中，厚度为 0.8 mm 的薄铝合金板采用 0 和 0.1 mm 的小肩部插入深度搅拌摩擦搭接焊接。研究了接头的形成、微观结构和力学性能。结果表明，当使用 0 mm 的小切入深度时，搅拌区内部会出现空隙，因为工具肩部在如此低的切入深度下无法发挥良好的材料收集效果。0.1mm的切入深度使台肩与物料接触紧密，收料效果好，有利于消除空隙。当使用 0.1 毫米的肩部插入深度时，可以在各种焊接参数下获得良好的接头。结合韧带内部未观察到裂纹。在搭接剪切试验期间，当接头的后退侧 (RS) 承受主要载荷时，接头具有更高的破坏载荷。剪切破坏载荷随着旋转和焊接速度的增加先增加后减小，在600 rpm和150 mm / min时获得6419 N的最大破坏载荷。接头硬度呈“W”形，在热影响区硬度最小。当前进侧和RS分别承受主要载荷时，接头呈现拉伸断裂和剪切断裂。接头硬度呈“W”形，在热影响区硬度最小。当前进侧和RS分别承受主要载荷时，接头呈现拉伸断裂和剪切断裂。接头硬度呈“W”形，在热影响区硬度最小。当前进侧和RS分别承受主要载荷时，接头呈现拉伸断裂和剪切断裂。