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Polysynthetic twinned TiAl single crystals for high-temperature applications
- Source :
- Nature materials. 15(8)
- Publication Year :
- 2015
-
Abstract
- TiAl alloys are lightweight, show decent corrosion resistance and have good mechanical properties at elevated temperatures, making them appealing for high-temperature applications. However, polysynthetic twinned TiAl single crystals fabricated by crystal-seeding methods face substantial challenges, and their service temperatures cannot be raised further. Here we report that Ti-45Al-8Nb single crystals with controlled lamellar orientations can be fabricated by directional solidification without the use of complex seeding methods. Samples with 0° lamellar orientation exhibit an average room temperature tensile ductility of 6.9% and a yield strength of 708 MPa, with a failure strength of 978 MPa due to the formation of extensive nanotwins during plastic deformation. At 900 °C yield strength remains high at 637 MPa, with 8.1% ductility and superior creep resistance. Thus, this TiAl single-crystal alloy could provide expanded opportunities for higher-temperature applications, such as in aeronautics and aerospace.
- Subjects :
- 010302 applied physics
Materials science
Mechanical Engineering
Metallurgy
02 engineering and technology
General Chemistry
021001 nanoscience & nanotechnology
Condensed Matter Physics
01 natural sciences
Jet engine
law.invention
Creep
Mechanics of Materials
law
0103 physical sciences
Degradation (geology)
General Materials Science
0210 nano-technology
Ductility
Subjects
Details
- ISSN :
- 14764660
- Volume :
- 15
- Issue :
- 8
- Database :
- OpenAIRE
- Journal :
- Nature materials
- Accession number :
- edsair.doi.dedup.....97c4316b94a4f8d34a079696049696a7