Compaction and characterization of mechanically alloyed nanocrystalline titanium aluminides
- Univ. of Idaho, Moscow, ID (United States)
- Lockheed-Martin Idaho Technologies Co., Idaho Falls, ID (United States). Metals and Ceramics Div.
Titanium aluminides ({alpha}{sub 2}Ti{sub 3}Al and {gamma}-TiAl) are attractive candidate materials for aerospace structural and engine applications due to their low density, high specific strength, elevated temperature strength, modulus retention, and excellent creep resistance. Blended elemental (BE) Ti-24 at. pct Al-11 at. pct Nb (Ti-24-11) and Ti-55 at. pct Al (Ti-55) powders and prealloyed (PA) Ti-24-11 powders were mechanically alloyed in a SPEX mill or an attritor. After SPEX milling for 10 hours, the BE Ti-24-11 powder contained the B2/bcc phase, while the BE Ti-55 powder showed the presence of an amorphous phase. The PA Ti-24-11 powder containing the B2 phase showed a decrease of crystal size on milling. These powders were consolidated by hot isostatic pressing (hipping), Ceracon process, and dynamic methods. On compaction, the B2/bcc phase in the Ti-24-11 sample transformed to a mixture of the B2 and orthorhombic (O) phases, while the amorphous phase in the Ti-55 powder crystallized to a mixture of the {gamma}-TiAl and {alpha}{sub 2}-Ti{sub 3}Al phases. The finest grain size in compacted material was obtained in the dynamically consolidated powder, and the grain size in the hot isostatic pressed (hipped) powder became larger with the increasing hipping temperature.
- Sponsoring Organization:
- USDOE Idaho Operations Office, Idaho Falls, ID (United States)
- DOE Contract Number:
- AC07-76ID01570
- OSTI ID:
- 474114
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 28, Issue 2; Other Information: PBD: Feb 1997
- Country of Publication:
- United States
- Language:
- English
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