Abstract:Specimens of Sn-Pb-0.05RE solder alloy were tested to failure under two different stress states,uniaxial tension using smooth bar specimens and triaxial tension using notched bar specimens. The tests were conducted at a temperature of 125℃, far above 0. 5 melting temperature of Sn-Pb-0.05RE solder alloy,which leads to a distinctive creep deformation. Rupture times were compared for uniaxial and triaxial stress states with respect to multiaxial stress parameters that are directly related to physical fracture mechanisms.The success of the parameters was judged according to how well the stress parameters correlate with the time to rupture. The results show that the Mises effective stress is the stress factor which dominates the creep rupture of Sn-Pb-0. 05RE solder alloy. It further suggests that the cavity nucleation on a grain boundary plays an important role in the creep rupture process of Sn-Pb-0.05RE solder alloy.

Key words:  Sn-Pb-0.05RE soder alloy; creep rupture; stress factor; multiaxial stress