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Crack Growth Rate Behaviour and Microstructural Features of Incoloy 800H under Fatigue and Creep-fatigue Conditions
Last modified: 2013-05-03
Abstract
Incoloy 800H is a solid-solution-strengthened iron-based austenitic alloy. In this
study, the alloy was forged and solution heat treated followed by annealing at
982°C for three hours. Fatigue and creep-fatigue (10 and 30 second dwell) crack
growth rate tests were performed using a fully automated DCPD technique to
monitor crack growth. The results indicate that the growth rates of the creepfatigue
conditions are ten times faster than those of the fatigue condition at the
same K values. Similar crack growth rates between a 10 second and 30 second
dwell was observed. The predominant fracture mode in both conditions was
transgranular. Continuous stable oxides and oxide penetration due to internal
oxidation associated with the chromium depleted zone were observed only in
creep-fatigue crack growth rate tests.
study, the alloy was forged and solution heat treated followed by annealing at
982°C for three hours. Fatigue and creep-fatigue (10 and 30 second dwell) crack
growth rate tests were performed using a fully automated DCPD technique to
monitor crack growth. The results indicate that the growth rates of the creepfatigue
conditions are ten times faster than those of the fatigue condition at the
same K values. Similar crack growth rates between a 10 second and 30 second
dwell was observed. The predominant fracture mode in both conditions was
transgranular. Continuous stable oxides and oxide penetration due to internal
oxidation associated with the chromium depleted zone were observed only in
creep-fatigue crack growth rate tests.
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