Host: The Japan Society of Mechanical Engineers
Name : International Conference on Power Engineering-2021(ICOPE-2021)
Date : October 17, 2021 - October 21, 2021
To understand crack growth mechanisms for structural components used in power plants, crack growth tests were conducted in steam and air environments at 600 °C at cyclic loading frequencies from 0.1 Hz to 0.01 Hz using a compact tension specimen, aiming to clarify the specific environmental effect on the crack growth rate (CGR) and the acceleration factor in steam and dry air environments. After the tests, the morphology and elemental distributions of formed oxides and precipitates on the fracture surfaces and at around fatigue crack tip region were analyzed scanning electron microscopy. The fracture surfaces of the crack that propagated in a steam environment were more undulated compared to those observed in a dry air environment irrespective of the loading frequency. All the examined crack tips were filled with oxides. The relationship between the CGR and the thickness of formed oxides were obtained. A linear dependence was exhibited in each loading frequency irrespective of the tested environments. It was revealed that the increase in the oxide formation was an acceleration factor of the CGRs.
