Early experiments that verify the diffusional creep rate predictions of Nabarro and Herring were undertaken just below the melting temperature and on small diameter wires and thin foils with through thickness grains. Results were shown to give reasonable agreement with predictions at sufficiently long test durations but specimens of other geometries and grain shapes have shown more variability. Recently some of these results have been re-interpreted and the applicability of the Nabarro-Herring creep mechanism to them has been questioned. Further experiments have been carried out in the present work on a number of pure metals to determine possible sources of the experimental diversity and to re-evaluate operative mechanisms.
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