多场耦合条件下Cu/SnBi-xSm/Cu微焊点界面IMC生长行为的研究

Study on Interfacial IMC Growth Behavior of Cu/Sn Bi-x Sm/Cu Microsolder Joint under Multi-field Coupling Condition

采用超声协振复合钎焊技术制备Cu/Sn58Bi-x Sm/Cu微焊点,并通过自主研发的多场耦合时效装置,进一步研究在热场、电场、磁场和力场的四维多场耦合条件下,微焊点界面IMC（intermetallic compound）的微观组织变化和力学行为。结果表明：严酷多场耦合条件下,钎焊焊点热端IMC层逐渐变厚,其形状趋于平整;冷端逐渐变薄,其形状呈现出锯齿状。当添加的Sm含量为0.05%时,微焊点表现出良好的力学性能。随着多场耦合作用时间的增加,焊点的抗拉强度均有所下降,且拉伸断口的解理台阶变宽,气孔、夹杂数量增加,小裂纹发展为大裂纹,其数目也增多。

The Cu/Sn58 Bi-x Sm/Cu microsolder joint was prepared by using ultrasonic vibration composite brazing technology. The microstructure change and mechanical behavior of IMC phase on the interface of microsolder joint under the four-dimensional multi-field coupling condition including thermal field, electric field, magnetic field and force field were studied by using self-developed multi-field coupling aging device. The results show that under the harsh multi-field coupling condition, the IMC layer at hot-end of the solder joint thickens, its shape tends to be smooth, and the IMC layer at cold-end becomes thinner and serrated. When the addition of Sm content is 0.05%, the microsolder joint has good mechanical properties. With the increase of the multi-field coupling time, the tensile strength of the solder joint decreases, and in tensile fracture, the cleavage step becomes wider, the quatity of stomata and inclusions increase, microcracks develop to large cracks,and the quatity of the cracks also increases.