Influence of grain orientation on the incipient oxidation behavior of Haynes 230 at 900°C

• Published in: Materials characterization 2015-09, Vol.107, p.33-42
• Main Authors: Wang, Xu, Fan, Fan, Szpunar, Jerzy A., Zhang, Lina
• Format: Article
• Language: English
• Subjects: ALLOYS; ANISOTROPY; ATOMIC FORCE MICROSCOPY; Atomic force microscopy (AFM); BACKSCATTERING; CORRELATIONS; CRYSTALLOGRAPHY; Deviation angle; Electron backscattering diffraction (EBSD); ELECTRON DIFFRACTION; GRAIN ORIENTATION; HAYNES ALLOYS; MATERIALS SCIENCE; Ni-based superalloy; OXIDATION; SOLID OXIDE FUEL CELLS; SURFACES; TEMPERATURE RANGE 1000-4000 K
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2015.06.029

Ni-based superalloy Haynes 230 is used in many applications such as very high temperature reactor (VHTR) or solid oxide fuel cells (SOFCs) where it is exposed to high temperature service environment. In order to improve the resistance for high temperature oxidation, the effect of crystallographic orientation on the early stage oxidation was investigated. It was demonstrated that different oxide thicknesses are formed on grains having different orientations. Comparison of electron backscatter diffraction (EBSD) orientation maps before and after oxidation at 900°C indicates that grains near (111) orientation, especially with the deviation angle from that is smaller than 20°, are more oxidation resistant than grains of other orientations. Correlation between the results of electron backscatter diffraction (EBSD) and atomic force microscopy (AFM) was used to compare the oxidation rate of grains having different crystallographic orientation. The oxidation rate was found to change with the crystallographic orientation as follows (111)