Constitutive behavior of Sn3.8Ag0.7Cu and Sn1.0Ag0.5Cu alloys at creep and low strain rate regimes

D. Bhate, D. Chan, G. Subbarayan, T. C. Chiu, D. Edwards, V. Gupta

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

Abstract

Constitutive models for SnAgCu solder alloys are of great interest at the present. Commonly, constitutive models that have been successfully used in the past for Sn-Pb solders are used to describe the behavior of SnAgCu solder alloys. Two issues in the modeling of lead-free solders demand careful attention: (i) Lead-free solders show significantly different creep strain evolution with time, stress and temperature, and the assumption of evolution to steady state creep nearly instantaneously may not be valid in SnAgCu alloys and (ii) Models derived from bulk sample test data may not be reliable when predicting deformation behavior at the solder interconnection level for lead-free solders due to the differences in the inherent microstructures at these different scales. In addition, the building of valid constitutive models from test data derived from tests on solder joints must deconvolve the effects of joint geometry and its influence on stress heterogeneity. Such issues have often received insufficient attention in prior constitutive modeling efforts. In this study all of the above issues are addressed in developing constitutive models of Sn3.8Ag0.7Cu and Sn1.0Ag0.5Cu solder alloys, which represent the extremes of Ag composition that have been mooted at the present time. The results of monotonie testing are reported for strain rates ranging from 4.02E-6 to 2.40E-3 s-1. The creep behavior at stress levels ranging from 7.8 to 52 MPa are also described. Both types of tests were performed at temperatures of 25°C, 75°C and 125°C. The popular Anand model and the classical time-hardening creep model are fit to the data and the experimentally obtained model parameters are reported. The test data are compared against other reported data in the literature and conclusions are drawn on the plausible sources of error in the data reported in the prior literature.

Original languageEnglish (US)
Title of host publicationProceedings of the ASME International Mechanical Engineering Congress and Exposition, IMECE 2007
Pages183-196
Number of pages14
DOIs
StatePublished - May 28 2008
Externally publishedYes
EventASME International Mechanical Engineering Congress and Exposition, IMECE 2007 - Seattle, WA, United States
Duration: Nov 11 2007Nov 15 2007

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings
Volume5

Other

OtherASME International Mechanical Engineering Congress and Exposition, IMECE 2007
CountryUnited States
CitySeattle, WA
Period11/11/0711/15/07

ASJC Scopus subject areas

  • Engineering(all)

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    Bhate, D., Chan, D., Subbarayan, G., Chiu, T. C., Edwards, D., & Gupta, V. (2008). Constitutive behavior of Sn3.8Ag0.7Cu and Sn1.0Ag0.5Cu alloys at creep and low strain rate regimes. In Proceedings of the ASME International Mechanical Engineering Congress and Exposition, IMECE 2007 (pp. 183-196). (ASME International Mechanical Engineering Congress and Exposition, Proceedings; Vol. 5). https://doi.org/10.1115/IMECE2007-44151