Sn-Pb系およびSn-Ag系共晶はんだの硬さ試験による力学特性評価

A convenient method for evaluating mechanical properties of solder materials was proposed in this study. In the method, Vickers hardness was evaluated by time dependent expression, HV=HV0·tcv, where HV and tv are Vickers hardness and indenting time. Two material parameters, i.e. HV0 and c, are related to the hardness without creep contribution and the significance of creep deformation, respectively. Above method was performed at room temperature for eutectic solders of Sn-37Pb and Sn-3.5Ag aged at three levels of aging temperature, Ta<10°C, Ta=R.T., 125°C (Sn-37Pb) and 160°C (Sn-3.5Ag). Finite element analysis was performed to simulate the Vickers indentation based on the elastic-plastic-creep deformation in order to correlate HV0 and c with yield stress and Norton's law for creep deformation. Using the proposed method, aging effect on the mechanical properties for the two systems of eutectic solders was also investigated.