The thermal-mechanical fatigue tests were carried out at the different temperatures, axial push pull loading and both coupling cases. So that investigate the fatigue stress and/or strain in surface of specimens for Sn/Pb solder joints. Moreover, the relationship between the thermal-mechanical cyclic stress and strain were discussed for estimation the fatigue stress/strain as well as fatigue crack growth rate. According to the results of the thermal-mechanical strain to be analyzed, the thermal-mechanical fatigue stress or strain can be nearly estimated by the experimental results. And the fatigue crack growth rate can also be expressed by the term /spl Delta//spl epsi//sub eqp.//sup n'/ l using the measured strain range under the disproportional loading of thermal-mechanical coupling. The results were compared with both 62Sn38Pb and 62Sn36Pb2Ag in different experimental data. On the other hand, experimentally obtained the either thermal, mechanical or both coupling fatigue crack growth rate can be evaluated based on the small crack growth law, for many electronic solder joints materials. It is possible that thermal-mechanical fatigue crack growth rate the solder joints or/and fatigue life easily and practically predicted based on the small crack growth law.
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