石墨烯纳米片增强的Sn-58Bi/Cu焊点可靠性

将不同含量（0%，0.025%，0.05%，0.075%，0.1%，0.2%，质量分数）的石墨烯纳米片（GNSs）添加到Sn-58Bi低温钎料中，研究了GNSs对钎料熔化温度、润湿性能、剪切强度、显微组织和界面反应的影响。结果表明：添加GNSs可以改善Sn-58Bi钎料焊点的润湿性能和抗剪切强度，但对其熔化温度的影响较小。随着GNSs的添加，钎料得到了相对细化的显微组织，界面金属间化合物（IMC）的厚度明显降低，并逐渐趋于平整。另外，随着GNSs的加入，Sn-58Bi钎料的剪切断裂模式从脆性断裂转变为脆性和韧性混合的断裂模式，这与其抗剪切强度的变化是一致的。因此，添加微量的GNSs是增强Sn-58Bi/Cu焊点可靠性的有效途径。

Reliability of Graphene Nanosheets-Reinforced Sn-58Bi/Cu Solder Joints

Graphene nanosheets (GNSs) of different mass fractions (0wt%, 0.025wt%, 0.05wt%, 0.075wt%, 0.1wt%, and 0.2wt%) were added into the Sn-58Bi low-temperature solder. The influences of GNSs on melting characteristics, wettability, shear properties, microstructure and interfacial reaction were investigated. Results show that adding GNSs has the positive effect on the wettability and shear strength of Sn-58Bi solder joint, and a slight influence on the melting temperature. After the addition of GNSs, a finer microstructure of Sn-58Bi solder is obtained. The thickness of intermetallic compound (IMC) at solder/Cu interface reduces significantly and the IMC morphology becomes flat after adding GNSs. In addition, with the addition of GNSs, the shear fracture mode of Sn-58Bi low-temperature solder converts from brittle into a mixed mode of brittle and ductile fracture, which is coincident with the changing situation of shear strength. In general, adding GNSs may be conducive to the improvement of solder joint reliability.