Paper Titles
Atomic Migration as a Mechanism of Superstructure Formation in Intermetallic Compounds
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Aging of Oxides under Irradiation
p.621
Modelling, Simulations and Monitoring of Lamella Structure Formation in Titanium Alloys Controlled by Diffusion Redistribution
p.635
Modelling of Phase Transformations in Substitutional Alloys
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Thermo Mechanical Treatment of Nickel and Titanium Aluminides
p.653
Effect of Self-Interstitial Diffusion Anisotropy in Electron-Irradiated Zirconium. A Cluster Dynamics Modeling
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Phase Transformation and Densification of Nanostructured Alumina. Effect of Seeding and Doping
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Kinetics of Precipitation: Comparison between Monte Carlo Simulations, Cluster Dynamics and the Classical Laws
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Evidence for a Diffusion-Based Mechanism of Liquid Metal Intergranular Penetration: Case Study of a Ni-Bi Model System
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Thermo Mechanical Treatment of Nickel and Titanium Aluminides

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Abstract:

Polycrystalline Ni3Al and TiAl are attractive materials for high temperature structural applications due to their stability in oxidizing and sulphidizing environment upto700 0 C. They possess significantly higher specific stiffness and similar specific strength as that of super alloys. Hence, these materials can replace super alloys for high temperature applications (~900°C). TiAl has lesser density and can be used for reducing component weight up to 50% and suitable for aerospace and automobile (high performance vehicles) sectors. The major difficulty for putting Ni3Al for engineering applications is its extremely low ductility and inter-granular fracture at ambient temperatures. TiAl, apart from the said brittleness it also suffers from high temperature corrosion. However the brittleness of these aluminides can be reduced by micro-alloying and by subjecting them to Thermo Mechanical Treatments, TMT. This paper deals with the recrystallization studies on nickel aluminides, deformed to different extents by rolling. The average grain size dependence with the % elongation is evaluated in the grain size range of 10-35micron. For the nickel aluminide deformed for 50% by rolling, the variation of resistivity and hardness with annealing time is determined. The homogenized TiAl samples were cold worked and annealed at 1000 0 C. Since the aluminide suffers from low ductility at room temperature, an arbitrary parameter, electrical resistivity, was chosen. Corresponding hardness values were also obtained. Finally a qualitative determination of ductility was made by studying the flow behavior of alloy around the hardness indentation. Thus a correlation was developed between resistivity, hardness and ductility values. It was then to some extent possible to investigate the TMT cycles on the microstructure and hence on the ductility of the TiAl without going for the actual tensile tests.

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Periodical:

Defect and Diffusion Forum (Volumes 237-240)

Pages:

653-658

DOI:

https://doi.org/10.4028/www.scientific.net/DDF.237-240.653

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Online since:

April 2005

Authors:

Vijaya Agarwala, Joanna Karwan-Baczewska

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© 2005 Trans Tech Publications Ltd. All Rights Reserved

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