Characterization of Indalloy 227 non lead solder

Matthew Hall Beaumont, Purdue University

Abstract

The mechanical behaviour of Indalloy 227 was investigated. A modified Johnson-Cook model was used to model the temperature and strain rate dependent plastic behaviour for higher strain rates (10−4 to 10 −1). The superplastic behaviour for the lower strain rates (10 −5 to 10−9) of the steady state creep domain was modeled with a power law creep model. A microstructural parameter was introduced into the model in the form of the average grain size. A three dimensional model was extrapolated from the one dimensional creep tests and verified through experimental results. The creep model was used with a commercial finite element package. The finite element analysis successfully modeled tests involving stress relaxation and shear of a bar of the solder. The primary creep of the solder was found to be of negligible magnitude for most applications, so the total creep model reduces to the steady state model for any deformation resulting in greater than 0.1% strain. A parametric study was performed using the creep model in a finite element package, investigating the effect of solder ball height, number of solder balls, and the effect of thermal cycling on the stress state within multiple solder balls.

Degree

Ph.D.

Advisors

Sun, Purdue University.

Subject Area

Materials science

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