High-temperature oxidation mechanisms of nano-/submicro-scale lamellar structures in an intermetallic alloy. (October 2019)

• Record Type: Journal Article
• Authors: Wu, G.D.; Cui, G.R.; Qu, S.J.; Feng, A.H.; Cao, G.J.; Ge, B.H.; Xiang, H.P.; Shen, J.; Chen, D.L.
• Is Part Of: Scripta materialia. Number 171(2019)
• Page Start: 102
• Page End: 107
• Publication Date: 2019-10
• Subjects: Oxidation -- γ-TiAl/α2-Ti3Al lamellae -- First-principles calculation -- κ-Al2O3 -- α-Al2O3; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2019.06.028
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: The aim of this study was to elucidate the oxidation mechanisms of γ-TiAl/α2 -Ti3 Al lamellar structures in a TiAlNbCr intermetallic alloy at a high temperature. The original γ-TiAl/α2 -Ti3 Al lamellae in the alloy were transformed into H-Ti2 AlN/α2 -Ti3 Al lamellae, and κ-Al2 O3, α-Al2 O3 and some remaining γ-TiAl phases were observed to be co-existent. The first-principles calculations of density-functional type based on the generalized-gradient approximation revealed that the metastable κ-Al2 O3 can be converted into the stable α-Al2 O3 . TiN and Ti2 AlN could be converted into each other to form κ-Al2 O3 under specific conditions. Thus the oxidation path of the intermetallic alloy is established as follows: γ − TiAl → ( H − Ti 2 AlN, TiN ) → κ − Al 2 O 3 → α − Al 2 O 3 . Graphical abstract: Unlabelled Image