【摘要】 针对7475铝合金回填式搅拌摩擦点焊(FSSW)展开研究,首先采用不同工艺参数对2mm7475铝合金进行焊接,然后对焊点表面和横截面进行观察,同时对试样进行硬度测量和拉伸剪切测试。结果表明,根据焊缝微观组织可以将焊点分为4个部分,不同部位的晶粒尺寸不同;并在微观组织中发现了Hook、孔洞和未连接等由于材料流动性不佳造成的微观组织缺陷;同时,母材区和搅拌区的硬度明显高于热影响区和热机影响区;另外,焊点的最高硬度和拉伸剪切强度随着焊具旋转速度、搅拌套下压深度的变化而呈现规律性变化,但是搅拌套运动速率对焊点力学性能的影响不明显。更多还原

【Abstract】 The 7475 aluminum alloy backfill friction stir spot welding(FSSW) was studied. Firstly, the 2 mm 7475 aluminum alloy was welded by different process parameters, then the surface and cross section of the joint were observed, and the hardness and tensile shear test of the sample were carried out. The results show that the joint can be divided into four parts according to the weld microstructure, and the grain size of different parts is different. Hook, holes and unjointed microstructures due to poor fluidity of the material are found in the microstructure. At the same time,the hardness of the base metal zone and stirring zone is significantly higher than that of the heat affected zone and the thermo-mechanically affected zone; in addition, the highest hardness and tensile shear strength of the joint vary with welding tool rotation speed and the depth of the sleeve. However, the effect of the stirring sleeve movement rate on the mechanical properties of the solder joint is not obvious.更多还原