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Abstract
The influence of atmospheres of differing oxidizing potential (up to 1 × 10−3 atm (101 N/m2) pressure of oxygen) on the tensile creep of high-purity iron has been studied in the range 1050–1100°C (1323–1373 K). The creep rate at 1096°C (1369 K) increased and the time to failure decreased with increasing oxygen pressure in continuously oxidizing conditions. Preoxidation at 1081° C (1354 K), before creep testing in non-oxidizing conditions, increased the extent of substrate cavitation, which promoted a higher creep rate and reduced time to failure. A greater number of metal surface cracks occurred in oxidizing atmospheres compared with inert conditions. Crack growth and crack linking took place between grain-boundary oxides and substrate cavities.