Influence of Test Temperature, Strain Frequency and Strain Hold on Fatigue Life of Eutectic Solder 63 Sn-37 Pb

Abstract

The torsional fatigue tests of bulk 63 Sn-37Pb solder were carried out under the condition of test temperature 233-393 K, strain frequency 0.5-0.005Hz and strain hold time 0-99 sec. The followings were shown from the results of the tests in which the test temperature and the strain frequency were varied. The fatigue life was determined only by the inelastic strain range of the stress-strain loop, not influenced by the test temperature and strain frequency. Coffin-Manson law held good in the relationship between the fatigue life and the inelastic strain range. While, in the case of the test in which the strain hold was added, the fatigue life correlated to the inelastic strain range, decreased by the strain hold in the case that the ramp (strain change slope) time was short. In the case that ramp time was long, however, it did not decrease and the Coffin-Manson relation was similar to that of non hold. In this case, the data were able to be put ingood order by assumption that linear damage law held good on the ramp damage and the hold damage respectively.