圧子圧入法による鉛フリーはんだの力学特性の予測

概要

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A convenient method for predicting mechanical properties of solder materials was proposed in this study. Indentation method was used to obtain mechanical properties including elastic, plastic and creep deformations. Elastic-plastic finite element method (FEM) correlated Young's modulus, E, and yield stress, σ_<ys>, with unloading portion of load-displacement curve and Vickers hardness, HV, respectively. The creep properties of solders were evaluated by the Norton's law, ε^・=A・σ^n. Indentation creep and tensile creep deformations were correlated by elastic-plastic-creep FEM analysis, and the latter could be directly predicted by the former. The agreement of the prediction was confirmed for Sn-37Pb eutectic solder in the range between room temperature and 125℃. Using the proposed method, mechanical properties of lead-free solders such as Sn-3.5Ag and Sn-3Ag-0.5Cu-0〜3Bi alloy systems were determined. The predicted results revealed that mechanical properties of Sn-3.5Ag and Sn-3Ag-0.5Cu alloys were similar, and that E, σ_<ys> and activation energies for creep of Sn-3Ag-0.5Cu-0〜3Bi lead-free solders tended to increase with increasing Bi content.
社団法人日本材料学会の論文
2002-04-15