Yb元素对BAg30硬钎料及焊点组织与性能的影响

Influences of Ytterbium on Microstructure and Properties of BAg30 Filler Metals and Brazed Joints

研究了Yb元素对Ag30-Cu-Zn-Sn(BAg30)钎料热性能、润湿性和微观组织的影响,分析了焊点的剪切强度和断口形貌,优化了钎料组分。结果表明,BAg30钎料添加1%(质量分数,下同)Yb后可以显著降低钎料液相线-固相线差值,促进钎料在钢基板表面的润湿性,细化微观组织。然而,当Yb添加量超过1%后,过量的Yb元素会降低钎料的性能,粗化微观组织。通过焊点剪切测试,BAg30-1%Yb钎料的焊点抗剪切强度和断裂形貌表现出明显的优越性,抗剪切强度相较于BAg30钎料焊点明显提高,断口形貌出现均匀细小的韧窝,表现为韧性断裂机制。

The effects of ytterbium(Yb) on the thermal behavior, wettability, and microstructures of Ag30-Cu-Zn-Sn(BAg30) filler metals were investigated. The shear strength and fracture morphology of brazed joints were analyzed to optimize the filler composition. Results reveal that the addition of 1wt% Yb in BAg30 filler metal can significantly decrease the temperature difference between solidus temperature and liquidus temperature, improve the wettability of filler on the steel substrate, and refine the microstructures. However, the excessive addition of Yb(more than 1wt%) can degrade the properties and coarsen the microstructure.According to the shear strength tests, the BAg30-1wt% Yb brazed joint shows obvious superiority in shear strength and fracture morphology: its shear strength is higher than that of the original BAg30 brazed joint, and the fracture mechanism is ductile fracture,presenting the homogeneous and fine dimples.