A Comparison of Viscoplastic and Plastic Constitutive Models for Pb/Sn Solder Alloys

Abstract In the literature there has been a number of constitutive models proposed for modeling thermomechanical behavior of Pb/Sn solder alloys. Some of these models are based on the plasticity (using time independent irreversible deformations), and some are based on the viscoplasticity (using time dependent irreversible deformations). In this paper it is demonstrated that Pb/Sn solder alloys are highly viscous materials, and that their behavior cannot accurately be modeled with a plasticity based model.