Creep Behavior Of Eutectic 63Sn37Pb And Sn0.7Cu Solder Alloys

63Sn37Pb eutectic solder has been widely used as an interconnection material due to its favorable properties and low price. The lead-free solder Sn0.7Cu which was less studied has high melting point,but it is inexpensive and it can be used in wave flow .In this dissertation,creep behavior of the two solder alloys was investigated.The main contents of this dissertation are as following.Tensile creep behaviors of conventional eutectic 63Sn37Pb solder alloy were investigated at 23℃,60℃,90℃and 120℃with the homemade creep testing machine. In this study, a miniature bulk specimen was used and the bulk specimen was of circular cross-section with a diameter of 1 mm and a gauge length of 2 mm. At the preceding temperature and applied stress range the steady-state creep rates were controlled by the dislocation climb mechanism. The best-fit exponent of 63Sn37Pb is 4.3, and creep equation is determined. Three models were used to predict the rupture times of the eutectic 63Sn37Pb solder. The results showed that creep rupture by necking and the model based on the continual nucleation of cavitating facets could make good agreement with the experimental data, but the Kachanov equation gave less accurate predictions.Tensile creep behaviors of eutectic Sn0.7Cu solder alloy were investigated at 23℃,60℃,90℃and 120℃with a miniature bulk specimen of circular cross-section . The threshold stress approach was used to describe the creep behavior. In the low temperature regime best-fit exponent was 7 and in the high temperature regime best-fit exponent was 5. Creep equation of Sn0.7Cu was determined.