Creep Behaviors Of Low-temperature Sintered Nanoscale Silver Paste At Elevated Temperatures

The creep behavior of nano-scale silver paste has been investigated in this thesis. The films of nano-scale silver paste were made with low-temperature sintered technology, according to the traditional sintered theory and the characteristics of nano particle. It is a porous silver film, with good conductivity and thermal conductivity.The creep tests have been performed for temperatures ranging from 100℃to 175℃and for stress from 2MPa to 7.5MPa. The study of the creep behavior of nano-scale paste has revealed an ordinary creep resistance in the experimental range. The steady-state creep stage occupied most of the creep time, it is similar with a lot of traditional metals. And the steady-state creep strain rate is about 10-6~10-8s-1. Moreover, Dorn Energy Law can be used to interpret phenomenally the relationship of the steady-state creep rate with stress and temperature.Many methods can be used for creep rupture life prediction of nano-scale silver paste. It is not appropriate that using empirical formula to predict the creep rupture life. Using the Monkman-Grant relationship can get a more accurate prediction, but the nano-scale silver paste must meet the Dorn Energy Law. Using approximate method obtained Larson-Miller parameter of nano-scale silver paste, and the variation of Larson-Miller parameter is visible.θprojection accurately describes the creep process of nano-scale silver paste film, and according this method, the more accurate steady-state creep strain rate can be obtained.The research of damage evolution of nano-scale silver paste film has revealed that this material reached 0.6 to 0.8 times of its creep rupture life. It became no longer safe. Using Robtonov damage theories and the power dissipation model to analyze, the results of the two damage theories were similar, but the Robtonov damage theory results are more conservative.