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Alloy steel; Alloys; Aluminum; Binary alloys; Ferrite; Grain boundaries; Iron alloys; Isotopes; Manganese; Manganese removal (water treatment); Oxidation; Oxygen; Secondary ion mass spectrometry; Silicon, Grain boundary oxidation; High temperature corrosions; Modelling studies; Numerical calculation; Oxidation behaviours; Oxygen isotope exchange; Oxygen transport; Selective oxidation, Internal oxidation
Abstract:
Selective oxidation experiments at 700. °C in binary and ternary iron-based model alloys containing Al, Cr, Mn, and Si were carried out. The internal oxidation behaviour along grain boundaries and inside ferrite grains was analyzed by LOM, SEM and ToF-SIMS. Oxygen isotope exchange revealed the location of fast diffusion pathways in the alloy. Numerical calculations of oxide distributions were compared to experimental findings, revealing that oxygen transport within ferrite grains is significantly lower than reported from literature. Discrepancies between simulations and experiments were discussed. The presented hypothesis of oxygen trapping represents an important viewpoint to explain internal oxidation in metallic alloys. © 2015 Elsevier Ltd.