Tensile properties of NiAl bicrystals
- Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering
The intermetallic compound {beta}-NiAl continues to receive considerable attention in spite of its lack of room temperature toughness and high temperature strength. Although the dislocations are mobile at room temperature, the lack of a sufficient number of slip systems precludes significant elongation in single and polycrystalline NiAl except in single crystals under special conditions. In the case of polycrystals of stoichiometric NiAl, the room temperature fracture tends to be mostly intergranular; this has been related to the stresses that build up at the grain boundaries during plastic deformation due to the lack of active independent deformation mechanisms or the possibility that the grain boundaries are intrinsically weak. The present study was designed to establish the condition of grain boundary fracture by performing tensile tests at different temperatures and strain rates on bicrystals of NiAl containing natural boundaries produced by Bridgman growth. This approach was selected based on the previous work on NiAl bicrystals produced by diffusion bonding/brazing and Bridgman growth. In some cases, these boundaries were reportedly enriched in nickel although it is unclear, based on the limited atomistic modeling efforts to date, whether this is a result of sample processing or is a characteristic of this compound. Furthermore, the previous studies of slip behavior were performed in compression which is less suitable for examining the relative strength of the grain boundaries.
- Sponsoring Organization:
- Department of the Air Force, Washington, DC (United States)
- OSTI ID:
- 603868
- Journal Information:
- Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 3 Vol. 38; ISSN 1359-6462; ISSN SCMAF7
- Country of Publication:
- United States
- Language:
- English
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