Title

Mechanical characterization of mechanically alloyed ultrafine-grained Ti5Si3+40 vol% gamma-TiAl composites

Authors

Authors

C. Suryanarayana; R. Behn; T. Klassen;R. Bormann

Comments

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Abbreviated Journal Title

Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process.

Keywords

Titanium alloys; Mechanical alloying; Mechanical characterization; Electron microscopy; Superplasticity; LOW-TEMPERATURE SUPERPLASTICITY; NANOCRYSTALLINE MATERIALS; TITANIUM; ALUMINIDES; NANOSTRUCTURED MATERIALS; FUTURE-DIRECTIONS; TENSILE; DUCTILITY; SIZE; METAL; DEFORMATION; BEHAVIOR; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering

Abstract

Ultrafine-grained ceramic-based composites of Ti-31.6Al-21.6Si (at%) consisting of 60 vol% of zeta-Ti5Si3 and 40 vol% of gamma-TiAl were produced by high-energy ball milling followed by hot isostatic pressing (HIP). Because of the cleanliness of the powder and full densification of the HIPed product, the mechanical behavior of the composite could be unambiguously related to the microstructure and chemistry. The starting microstructure after HIPing consisted of intermixed zeta-Ti5Si3 and gamma-TiAl phases of approximately equal grain size, the size ranging from about 300 nm to I pm depending on the HIP temperature. Hightemperature mechanical testing of this ultrafine-grained composite exhibited a strain-rate sensitivity of > 0.3. Further, the equiaxed microstructure was retained after mechanical testing, suggesting the possibility of achieving superplastic deformation. Consequently, tensile testing demonstrated elongations of about 150% at 950 degrees C and a strain rate of 4 x 10(-5) s(-1). Considering that the present alloy has the ceramic (suicide) phase as the matrix, this temperature at which superplastic deformation is observed is significantly lower than that reported for conventional coarse-grained ceramic materials. (C) 2013 Elsevier B.V. All rights reserved.

Journal Title

Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

Volume

579

Publication Date

1-1-2013

Document Type

Article

Language

English

First Page

18

Last Page

25

WOS Identifier

WOS:000321681900003

ISSN

0921-5093

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