At present, there have been many researches on the effect of trace elements on the mechanical properties of Sn–Ag–Cu solder, and the methods used are mainly shear test or nanoindentation test. However, the size of structural solder joints in electronic packaging has reached the order of micrometers, and the mechanical behavior characteristics related to the strain rate of solder at the micro-scale are obviously more needed for the application of small-scale structural solder joints. For this reason, this paper selects Sn0.3Ag0.7Cu solder with superior comprehensive properties such as ductility and shear strength and low cost, and uses universal testing machine and Split Hopkinson Pressure Bar to perform quasi-static and dynamic compression tests on it. After fitting the Johnson–Cook constitutive model parameters of Sn0.3Ag0.7Cu, the dynamic indentation process at the micro-scale was simulated by ABAQUS, and the effect of strain rate on the mechanical behavior of the material at the macro-scale and micro-scale was analyzed, respectively. Our macro test results show that the yield strength of Sn0.3Ag0.7Cu solder is about 28.74 MPa. Under quasi-static load, the rate of increase of the stress value in the strain hardening stage will increase with the increase of the strain rate; while under dynamic load, the stress value corresponding to different strain rates does not increase significantly, and the main difference lies in the magnitude of plastic strain. In our numerical simulation of dynamic indentation, the result shows that when Sn0.3Ag0.7Cu solder is subjected to a high strain rate load at the micro-scale, a certain degree of hardening occurs in the middle and late stages of indentation propagation. At the same time, the calculated load–displacement curves indicate that the plastic flow ability of Sn0.3Ag0.7Cu solder in the micro-scale increases with the increase of the indentation expansion rate.

目前，关于微量元素对Sn-Ag-Cu焊料力学性能的影响已有很多研究，所采用的方法主要是剪切试验或纳米压痕试验。然而，电子包装中结构焊点的尺寸已达到微米级，对于小规模结构焊点的应用，显然更需要与焊料的应变速率有关的机械行为特性。因此，本文选择具有延展性，剪切强度和低成本等综合性能优良的Sn0.3Ag0.7Cu焊料，并使用通用测试机和Split Hopkinson压杆对它进行准静态和动态压缩测试。拟合了Sn0.3Ag0.7Cu的Johnson-Cook本构模型参数后，利用ABAQUS模拟了微观尺度上的动态压痕过程，并从宏观和微观上分析了应变速率对材料力学行为的影响。我们的宏观测试结果表明，Sn0.3Ag0.7Cu焊料的屈服强度约为28.74 MPa。在准静态载荷下，应变硬化阶段应力值的增加率将随着应变率的增加而增加；在动载荷下，不同应变速率对应的应力值没有明显增加，主要区别在于塑性应变的大小。在我们的动态压痕数值模拟中，结果表明，当Sn0.3Ag0.7Cu焊料在微观尺度上承受高应变速率负载时，在压痕传播的中后期发生一定程度的硬化。同时，计算的载荷-位移曲线表明，Sn0.3Ag0.7Cu焊料在微观尺度上的塑性流动能力随着压痕膨胀率的增加而增加。