Viscoplastic Mechanics Constitutive Model Incorporating Void Damage for Pb/Sn Solder Alloys
Zhou Jun,Hao Weina,Chai Guozhong
(Zhejiang University of Technology, 310014, Hangzhou, China)

Abstract: The experiments in tension on eutectic SnPb material have been are carried out under various constant true strain rates ranging from 10E-5/s to 10E-3/s and at 298K~423K. Based on the experimental results the mechanical behavior of the material is investigated to reveal the presence of both the nucleation and growth deformation mechanisms of voids. A viscoplastic-damage constitutive model with void effects is proposed. Following the Gurson-Tvergaard-Needleman plastic potential equation and the orthogonal rules, the effect of void volume fraction is introduced into the material constitutive law to describe the mechanics behavior of eutectic solder alloy. Comparing with the various test data, it is verified that the capability of the viscopalstic model is capable of predicting stress-strain behaviors of eutectic SnPb solder under constant strain rate testing and steady state plastic flow.
Keywords: damage mechanics, void damage, eutectic solder alloy, constitutive model.