Hi Prasad,
At normal use conditions of soft solders they do not exhibit high-cycle
fatigue (HCF), that is fatigue determined by the ratio of strength over
modulus of elasticity rather than low-cycle fatigue (LCF) which is determined
by ductility. HCF would only be observable at very high strain rates (high
enough that they can not be obtained by thermal expansion mismatches) and at
low temperatures ( starting below -20C). It has nothing to do with the fact
that the loading of solder joints is strain-driven in actual use; you can run
stress-driven experiments.

Werner Engelmaier
Engelmaier Associates, Inc.
Electronic Packaging, Interconnection and Reliability Consulting
23 Gunther Street
Mendham, NJ  07945  USA
Phone & Fax: 973-543-2747
E-mail: [log in to unmask]

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