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Title: Long-term oxidation of orthorhombic alloy Ti-22Al-25Nb in air between 650 and 800 C

Abstract

Titanium alloys based on the orthorhombic phase Ti{sub 2}AlNb are currently under investigation for those aeroengine applications where the maximum service temperatures exceed the capabilities of conventional titanium alloys but are still lower than recommended for {gamma}-TiAl based aluminides. For some orthorhombic alloys, a better fracture toughness, higher ductility, higher specific yield and lower coefficient of thermal expansion for {gamma}-TiAl based alloys as well as for alpha-2 alloys has been reported and creep and fatigue behavior are similar to that of alpha-2 alloys. However, oxidation and embrittlement of orthorhombic alloys are a major concern when applications in the oxidizing atmosphere of an aeroengine and operating temperatures between 650 and 700 C are considered. The goal of the present study was to assess the long-term environmental resistance of high niobium-containing Ti-22Al-25Nb, an alloy presently under consideration for titanium matrix fiber reinforced composites (TMCs). TMCs are needed to introduce blisk (= bladed disk) and bling (= bladed ring) technology into modern aeroengine design. Oxidation tests on cast Ti-22Al-25Nb matrix material in laboratory air were conducted between 650 and 800 C up to 4,000 hr.

Authors:
 [1];  [2]
  1. DLR--German Aerospace Center, Koeln (Germany). Inst. of Materials Research|[Oak Ridge National Lab., TN (United States)|[Lawrence Berkeley National Lab., CA (United States)
  2. DLR--German Aerospace Center, Koeln (Germany). Inst. of Materials Research
Publication Date:
OSTI Identifier:
691366
Resource Type:
Journal Article
Journal Name:
Scripta Materialia
Additional Journal Information:
Journal Volume: 41; Journal Issue: 8; Other Information: PBD: 10 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; OXIDATION; TITANIUM ALLOYS; ALUMINIUM ALLOYS; NIOBIUM ALLOYS; CHEMICAL COMPOSITION; TEMPERATURE DEPENDENCE; TIME DEPENDENCE

Citation Formats

Leyens, C., and Gedanitz, H. Long-term oxidation of orthorhombic alloy Ti-22Al-25Nb in air between 650 and 800 C. United States: N. p., 1999. Web. doi:10.1016/S1359-6462(99)00234-1.
Leyens, C., & Gedanitz, H. Long-term oxidation of orthorhombic alloy Ti-22Al-25Nb in air between 650 and 800 C. United States. doi:10.1016/S1359-6462(99)00234-1.
Leyens, C., and Gedanitz, H. Fri . "Long-term oxidation of orthorhombic alloy Ti-22Al-25Nb in air between 650 and 800 C". United States. doi:10.1016/S1359-6462(99)00234-1.
@article{osti_691366,
title = {Long-term oxidation of orthorhombic alloy Ti-22Al-25Nb in air between 650 and 800 C},
author = {Leyens, C. and Gedanitz, H.},
abstractNote = {Titanium alloys based on the orthorhombic phase Ti{sub 2}AlNb are currently under investigation for those aeroengine applications where the maximum service temperatures exceed the capabilities of conventional titanium alloys but are still lower than recommended for {gamma}-TiAl based aluminides. For some orthorhombic alloys, a better fracture toughness, higher ductility, higher specific yield and lower coefficient of thermal expansion for {gamma}-TiAl based alloys as well as for alpha-2 alloys has been reported and creep and fatigue behavior are similar to that of alpha-2 alloys. However, oxidation and embrittlement of orthorhombic alloys are a major concern when applications in the oxidizing atmosphere of an aeroengine and operating temperatures between 650 and 700 C are considered. The goal of the present study was to assess the long-term environmental resistance of high niobium-containing Ti-22Al-25Nb, an alloy presently under consideration for titanium matrix fiber reinforced composites (TMCs). TMCs are needed to introduce blisk (= bladed disk) and bling (= bladed ring) technology into modern aeroengine design. Oxidation tests on cast Ti-22Al-25Nb matrix material in laboratory air were conducted between 650 and 800 C up to 4,000 hr.},
doi = {10.1016/S1359-6462(99)00234-1},
journal = {Scripta Materialia},
number = 8,
volume = 41,
place = {United States},
year = {1999},
month = {9}
}