Journal ArticleDOI
Superplastic behavior of two-phase titanium aluminides
TLDR
In this article, a two-phase Ti(57 at.pct)-Al(43 at. pct) alloy with an initial lamellar microstructure was thermomechanically processed to form an equiaxed fine-grained structure.Abstract:
A two-phase Ti(57 at. pct)-Al(43 at. pct) alloy with an initial lamellar microstructure was thermomechanically processed to form an equiaxed fine-grained structure. The fine-grained (- L = 5 μm) material was superplastic in the temperature range 1000 °C to 1100 °C, exhibiting a stress exponent of about 2 with a tensile ductility of 275 pct. The rate-controlling deformation mechanism is proposed to be grain boundary sliding accommodated by slip controlled by lattice diffusion in TiAl. At room temperature, the lamellar and fine-grained materials exhibit the same compressive yield stress. The compressive strain to failure, however, for the fine-grained material was about 28 pct compared to 6 pct for the lamellar material.read more
Citations
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Journal ArticleDOI
Hot workability of titanium and titanium aluminide alloys—an overview
TL;DR: In this article, the influence of hot working variables and microstructure on failure via fracture or flow-localization controlled processes is summarized for both conventional and isothermal hot working processes.
Journal ArticleDOI
Ordered intermetallic alloys: an assessment
TL;DR: In this paper, the authors summarized their present understanding of two classes of intermetallic alloys: nickel and iron aluminides, which are currently used by industries; and advanced intermetalloys including silicides and Laves-phase alloys, which have a great potential to be developed as new high-temperature structural materials for future industrial use.
Book ChapterDOI
Powder Metallurgy Processing
Randall M. German,R. G. Iacocca +1 more
TL;DR: The processing of intermetallic compounds has similarities to ceramic processing, as both ceramics and intermetallics are stoichiometric, with limited compositional ranges and brittle behavior Generally, the limited ductility forces a reliance on powder techniques for shaping and consolidation as mentioned in this paper.
Journal ArticleDOI
Superplastic behavior of a powder metallurgy TiAl alloy with a metastable microstructure
TL;DR: In this paper, a powder metallurgy (P/M) TiAl alloy with a metastable B2 phase coexisted with a fine-grained γ+α2 duplex structure has been studied and an elongation of over 300% was obtained at a strain rate of 2×10−5 s−1 and at a temperature of 800°C.
Journal ArticleDOI
Diffusion bonding of γ-TiAl sheets
TL;DR: In this article, the possibility of producing sound bonds in γ-TiAl sheets by industrially available diffusion bonding equipment designed for conventional Ti-alloys was investigated, and defect-free bonds were achieved at 1000°C with pressure levels of 5, 10 and 20 MPa, the holding time varying between 5 and 8 h.
References
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Journal ArticleDOI
Superplasticity—Recent advances and future directions
Oleg D. Sherby,Jeffrey Wadsworth +1 more
Journal ArticleDOI
Ordering transformations and mechanical properties of Ti 3 Ai and Ti 3 Al-Nb alloys
S. M. L. Sastry,H. A. Lipsitt +1 more
TL;DR: In this article, phase transformations and the kinetics of domain growth were studied in near stoichiometric Ti3Al and in a similar alloy containing about 5 at. pct Nb (Cb).