Fatigue crack initiation and growth in 43Fe-25Ni-22.5Cr austenitic steel at a temperature of 700 °C
| Autor: | Jaroslav Polák, Veronika Mazánová, Milan Heczko |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Austenite
Materials science Scanning electron microscope Mechanical Engineering Oxide 02 engineering and technology Intergranular corrosion 021001 nanoscience & nanotechnology Focused ion beam Industrial and Manufacturing Engineering chemistry.chemical_compound 020303 mechanical engineering & transports 0203 mechanical engineering chemistry Mechanics of Materials Modeling and Simulation mental disorders Scanning transmission electron microscopy General Materials Science Grain boundary Composite material 0210 nano-technology Electron backscatter diffraction |
| Zdroj: | International Journal of Fatigue. 114:11-21 |
| ISSN: | 0142-1123 |
| DOI: | 10.1016/j.ijfatigue.2018.04.033 |
| Popis: | Crack initiation and short crack growth in highly-alloyed austenitic steel Sanicro 25 cyclically strained at a temperature of 700 °C has been studied. Specimens cycled to 10% of the fatigue life and to the fracture were inspected using scanning electron microscopy and electron backscatter diffraction. On the surface, thin lamellae were extracted site-specifically by focused ion beam and then they were further characterized by high spatial resolution scanning transmission electron microscopy and energy dispersive X-ray spectroscopy. The preferential oxidation of grain boundaries was found to play a principal role in the initiation of multiple cracks. The oxide scale was analysed to show the distribution of individual elements during crack initiation and growth. Two types of crack paths were observed: intergranular due to the oxidation and transgranular accompanied by a cyclic plastic zone. Cracks preferentially initiated at the grain boundaries perpendicular to the stress axis and propagated in the bulk of the material. The role of the oxidation in high temperature fatigue crack initiation is discussed as well as the mechanisms of the crack initiation and growth. |
| Databáze: | OpenAIRE |
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