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Chromium alloys; Corrosion; Crack propagation; Cracks; Grain boundaries; High resolution transmission electron microscopy; High temperature operations; Iron alloys; Microstructure; Nanoindentation; Oxidation; Stress corrosion cracking; Ternary alloys; Transmission electron microscopy, Coupling condition; High temperature; Indenters; Micro-structure evolutions; Oxide grains; Sharp crack; Stress corrosion; Stress oxidation, High temperature corrosion
Abstract:
The microstructure evolution of a FeNiCr alloy oxidized at 600 °C by simultaneously applying stress via high temperature nanoindentation is reported. Analysis using transmission electron microscopy shows that a sharp crack was induced beneath the indentation area under the stress-oxidation coupling condition. Nanotwins beneath the indentation area were also observed, which acted as a barrier that ceased the crack propagation beneath the indenter by altering the path of the crack. Results reveal a transformation from inter-granular crack propagation along the oxide grain boundaries to intra-granular crack propagation through the nanotwin structure with a zig-zag pattern. © 2018 Elsevier Ltd
