Predicting solderability and the mechanical performance of complex solder joints requires constitutive equations that relate multiaxial stressing to the mechanical response of the solder. To address this need, the authors have investigated the effects of uniaxial tension and pure shear on the elastic, plastic, and fracture behavior of 63Sn-37Pb solder. Using standard tensile specimens, stress-strain curves were recorded at effective engineering strain rates between 0.0002 and 0.2 s/sup -1/. From these curves, young's modulus, 0.2% offset yield strength, ultimate tensile strength, and elongation to fracture were determined. Using similar torsion specimens, tests to examine shear behavior were conducted. From these tests, shear modulus, shear yield strength, and ultimate shear strength were determined for effective strain rates between approximately 0.0001 and 0.02 s/sup -1/. little or no effect of strain rate on Young's modulus or shear modulus was observed. The plastic properties (yield and ultimate strengths) in both tension and shear are strongly rate dependent and agree with the von Mises multiaxial yield theory. Fracture behavior (e.g. ductility) is strongly rate dependent.
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机译：预测复杂焊点的可焊性和机械性能需要将多轴应力与焊料的机械响应相关联的本构方程。为了满足这一需求，作者研究了单轴张力和纯剪切对63Sn-37Pb焊料的弹性，塑性和断裂行为的影响。使用标准拉伸试样，以0.0002至0.2 s / sup -1 /的有效工程应变率记录应力-应变曲线。从这些曲线确定杨氏模量，0.2％偏移屈服强度，极限抗拉强度和断裂伸长率。使用类似的扭转试样，进行了检查剪切性能的测试。从这些测试中，确定了在大约0.0001至0.02 s / sup -1之间的有效应变速率下的剪切模量，剪切屈服强度和极限剪切强度。几乎没有观察到应变速率对杨氏模量或剪切模量的影响。拉伸和剪切方面的塑性（屈服强度和极限强度）都与速率密切相关，并且与von Mises多轴屈服理论相符。断裂行为（例如延展性）在很大程度上取决于速率。
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