Abstract
The microstructures and properties of powder metallurgy (PM) TiAl alloys fabricated by hot-extrusion of gas-atomized powder at different temperatures (1150, 1250 and 1400 °C) have been investigated. Microstructure of the alloy fabricated at 1150 °C consists of fine grains of γ and α2 phases in association with coarse grains of B2 (ordered bcc) phase. Metastable ω particles of ordered hexagonal phase were observed within some B2 grains. This alloy (containing metastable B2 phase) displayed a low-temperature superplastic behavior, i.e. a tensile elongation of 310% was obtained when the alloy was tested at 800 °C under a strain rate of 2 × 10-5 s-1. Microstructure of the alloy fabricated at 1250 °C consists of coarse grains of α2 phase and fine grains of γ and α2 phases. This alloy (containing no B2 phase) on the other hand displayed no low-temperature superplasticity, as recorded from the alloy fabricated at 1150 °C. A refined fully lamellar (FL) microstructure was successfully developed within the alloys fabricated at 1400 °C. The widths of γ lamellae are in a range between 100 and 350 nm and the widths of α2 lamellae are in a range between 10 and 50 nm. Solute effects on the creep resistance of refined FL-TiAl alloy were critically investigated. © 2002 Elsevier B.V. All rights reserved.
| Original language | English |
|---|---|
| Pages (from-to) | 1-10 |
| Journal | Materials Science and Engineering A |
| Volume | 364 |
| Issue number | 1-2 |
| DOIs | |
| Publication status | Published - 15 Jan 2004 |
| Externally published | Yes |
Bibliographical note
Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].Research Keywords
- Alloy
- Microstructure
- Powder