Size and strain effect on miniature copper-solder-copper joint

摘要

In this study, miniature solder joint behaviors of Sn3.8Ag0.7Cu (SAC387) solder were tested and discussed for a range of geometrical ratios and strain rates at room temperature. Copper-solder-copper rod specimens were machined and soldered with SAC387 based on their specified geometrical ratio and then tested with an uni-axial load at a constant strain rate of 0.01^s−1. Orowan's approximation equation was used to make comparison with experimental results, followed by comparison of experimental results with the Finite Element Analysis (FEA) results. It was observed that variation of the geometrical ratio induced the formation of the dimensional constraining effect within the material. To study strain rate effect on copper-solder-copper joint, specimens with specified dimensions were tested with an uni-axial load at varying strain rate of 0.001^s−1, 0.01^s−1 and 0.1^s−1. Comparisons were conducted between the experimental and FEA simulated results. The increment in either the geometrical ratio of the solder or strain rate experienced within the joint was both noticed to lead to the deterioration of ductility but a simultaneous improvement in the brittle characteristic of the material.