Temperature and strain-rate dependent constitutive model for prediction of thermal cycling life

Abstract With temperature cycling as the characteristic working environment of aerospace electronic chips, various constitutive models have been proposed to predict the failure problems of solder joints. However, most researchers adopted only a set of constant parameters to describe the solder joint material properties throughout the temperature cycles, which is obviously unreasonable concerning the possible wide range of working temperature. In fact, with the changing temperature and strain rate, some material parameters will correspondingly evolve as observed in the experiments. In this paper, the framework of the Anand constitutive model is adopted to verify the effect of material parameters of different temperatures and strain rates on the mechanical properties of materials under the scenario of temperature cycling. The lead-containing solder alloy 63Sn37Pb material that is most widely used in aerospace is selected as the solder material for the interconnection structure. In addition, a typical plastic ball grid array (PBGA) packaging structure is used to analyze the influence of the constitutive model parameters on the PBGA thermal fatigue life. Based on experimental data, seven sets of constitutive model parameters with different temperatures (-55°C~125°C) under a region of low strain rate (1×10-4/s) were employed to compare the mechanical properties of the material under temperature cycling. The sensitivity analysis of material parameters is performed and the underlying mechanism are also explained so that the present study can promote the optimization of the constitutive model in numerical simulations in practice.