Oxidation behavior of two-phase {gamma} + {sigma} Nb-Ti-Al alloys

Journal Article · Tue Jun 01 04:00:00 EDT 1999 · Oxidation of Metals

DOI:https://doi.org/10.1023/A:1018899412977· OSTI ID:351493

Brady, M P ^[1]; Verink, Jr, E D ^[2]; Smith, J W ^[3]

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1. Oak Ridge National Lab., TN (United States)
2. Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering
3. NASA Lewis Research Center, Cleveland, OH (United States)

The oxidation behavior of a series of single- and two-phase Nb-Ti-Al alloys, selected from the same extended {gamma} + {sigma} tie-line, was investigated at 1200 C in air. The single-phase {sigma} alloy suffered from extensive internal oxidation and oxidized at a much higher rate than the single-phase {gamma} alloy. In a two-phase {gamma} + {sigma} microstructure, the {gamma} phase was preferentially attacked to form internal alumina and Ti-rich nitride. This preferential attack of {gamma} limited the extent to which the {sigma} phase was internally oxidized, but also interrupted the formation of a continuous alumina scale. The single-phase {gamma} alloy also did not form a continuous alumina scale. The inability of the {gamma} phase to form continuous alumina was attributed to a combination of nitride formation and internal oxidation. The oxidation behavior of the two-phase {gamma} + {sigma} Nb-Ti-Al alloys is discussed in terms of mechanisms developed for the oxidation of binary, two-phase alloys.

• DOE Contract Number: AC05-96OR22464
• OSTI ID: 351493
• Journal Information: Oxidation of Metals, Journal Name: Oxidation of Metals Journal Issue: 5-6 Vol. 51; ISSN OXMEAF; ISSN 0030-770X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
INTERMETALLIC COMPOUNDS
KINETICS
NIOBIUM ALLOYS
OXIDATION
SCALING
TEMPERATURE RANGE 1000-4000 K
TITANIUM ALLOYS