Ag (2.0 wt.%) and In (1.5 wt.%) were alloyed into Sn-58Bi eutectic solder, and the individual and combined influences of Ag and In on the microstructure, microhardness, and impact toughness of the SnBi solder were investigated. The results reveal that the microstructures of the SnBiAg, SnBiIn, and SnBiAgIn alloyed solders are coarser than that of the SnBi eutectic solder. Fine Ag3Sn particles are formed in the SnBiAg and SnBiAgIn solders, while small regions of In-rich phases appear in the SnBiIn and SnBiAgIn solders. The microhardness of the three alloyed solders are higher than the SnBi solder, and the Sn-rich phases in the alloyed solders show higher nanohardness, while the nanohardness of the Bi-rich phases with Ag and In addition changes little. The impact toughness of the SnBiAg, SnBiIn, and SnBiAgIn solders are observed to be higher than the SnBi solder, especially in the case of the SnBiAgIn solder. The improvement in ductility of the Sn-rich phase induced by the In solution, and the strengthening effect from the Ag3Sn particles are predicated to be the reason for the increase in impact toughness. The fracture surfaces demonstrate that plastic deformation of the SnBiAgIn solder during the impact process is more obvious. Overall, the combined addition of Ag and In can increase the microhardness and impact toughness of SnBi eutectic solder.

将Ag（2.0 wt。％）和In（1.5 wt。％）合金化成Sn-58Bi共晶焊料，并研究了Ag和In对SnBi焊料的微观结构，显微硬度和冲击韧性的单独和综合影响。结果表明，SnBiAg，SnBiIn和SnBiAgIn合金焊料的显微组织比SnBi共晶焊料的显微组织粗。在SnBiAg和SnBiAgIn焊料中会形成细小的Ag3Sn颗粒，而在SnBiIn和SnBiAgIn焊料中会出现富In相的小区域。三种合金焊料的显微硬度均高于SnBi焊料，合金焊料中的富Sn相表现出较高的纳米硬度，而富Ag和Bi的富Bi相的纳米硬度变化不大。SnBiAg，SnBiIn，观察到SnBiAgIn焊料和SnBiAgIn焊料的含量高于SnBiBi焊料，特别是在SnBiAgIn焊料的情况下。据推测，由In溶液引起的富Sn相的延展性的改善以及来自Ag 3 Sn颗粒的强化效果是冲击韧性提高的原因。断裂表面表明，在冲击过程中SnBiAgIn焊料的塑性变形更为明显。总体而言，Ag和In的组合添加可以提高SnBi共晶焊料的显微硬度和冲击韧性。断裂表面表明，在冲击过程中SnBiAgIn焊料的塑性变形更为明显。总体而言，Ag和In的组合添加可以提高SnBi共晶焊料的显微硬度和冲击韧性。断裂表面表明，在冲击过程中SnBiAgIn焊料的塑性变形更为明显。总体而言，Ag和In的组合添加可以提高SnBi共晶焊料的显微硬度和冲击韧性。