Interaction of Tantalum with Reinforcements in γ TiAl

Abstract

Evidence suggests that tantalum alloying additions can segregate to fiber or reaction zone interfaces in TiAl. The behavior depends on the reinforcing material being studied. Inhomogeneities in tantalum concentration in TiAl owing to segregation are a matter for concern. Other refractory metal additions may also segregate, since they behave similar to tantalum. Samples of Ti-47Al-2Ta with a few reinforcing fibers were hot isostatically pressed. The fibers used were Al2O3-ZrO2 and Si3N4, uncoated and coated with TiC or TiB2. These samples were heated for times up to 500 h at 982 °C in order to simulate potential use temperatures and times. Backscattered scanning electron microscopy, energy dispersive X-ray analysis and electron microprobe analysis were used for the examination. Results include a sixfold increase in tantalum at the interface between a TiB2 coating on a Si3N4 fiber and the matrix, while an uncoated fiber shows an increasing tantalum content in the fiber and reaction zones.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Alumina; Aluminum Alloys; Ceramic Fibers; Chemical Reactions; Fiber Reinforced Materials; Interfaces (materials); Metallic Matrix Composites; Silicon Nitride; Tantalum Alloys; Titanium Alloys; Zirconia; Titanium Aluminides; Titanium Aluminum Tantalum Alloys; Titanium Borides; Intermetallics

International Standard Serial Number (ISSN)

0921-5093

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1992 Elsevier, All rights reserved.

Publication Date

01 May 1992

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