ON THE CONSTITUTIVE RESPONSE OF 63 37-SN/PB EUTECTIC SOLDER/

The constitutive response of 63/37 Sn/Pb eutectic solder is studied un der uniaxial tension. Stress-strain tests were performed under a wide range of applied strain rate, and creep tests were performed at severa l levels of applied load. Temperature dependence was ascertained Ey ru nning the stress-strain and creep rests at various temperatures. With the goal of providing a constitutive description of the eutectic suita ble for use in electronics packaging engineering finite element analys es, the material parameters of the phenomenological viscoplasticity mo del of Bodner and Partom were fit to these experiments as functions of temperature. The experiments; described herein also yield important i nformation concerning how many microstructural units must be present i n a sample in order for repeatable, isotropic response to be obtained.