High-temperature deformation properties of NiAl single crystals

Journal Article · Wed May 01 04:00:00 EDT 1996 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02649860· OSTI ID:260341

Forbes, K R ^[1]; Glatzel, U ^[2]; Darolia, R ^[3]; Nix, W D ^[4]

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1. SEMATECH, Austin, TX (United States). Plasma Etch Dept.
2. Technical Univ. of Berlin (Germany). Inst. for Materials Science
3. GE Aircraft Engines, Cincinnati, OH (United States). Engineering Materials Technology Labs.
4. Stanford Univ., CA (United States). Dept. of Materials Science and Engineering

The high-temperature deformation properties of stoichiometric NiAl single crystals have been studied in the temperature range from 850 C and 1,200 C. The authors have established a basic data set for and have explored the high-temperature deformation characteristics of this intermetallic compound. The results provide a basis for determining the controlling mechanisms of high-temperature deformation. Constant stress tension creep and constant stress or constant strain rate compression experiments were conducted on crystals oriented with loading axes along the hard, [001] orientation, where no driving force exists for glide of b = <001> dislocations, and along various soft orientations, [223], [111], and [110], where deformation can occur by the glide of these dislocations. In addition to these monotonic tests, high-temperature deformation transients were studied using stress relaxation, strain rate change, and stress change experiments. Deformation in hard oriented crystals provides evidence for both mobility and substructure controlled deformation. Creep in hard oriented crystals is characterized by a dramatic sigmoidal transient suggesting very low dislocation mobility. However, the strain hardening observed in monotonic tests and the transient responses suggest that deformation is also limited by a dislocation substructure that forms during deformation. These findings support the conclusion, explored fully in a forthcoming article, that creep deformation in the hard orientation is controlled by the motion and interaction of b = <101> dislocations.

• Sponsoring Organization: USDOE
• OSTI ID: 260341
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 5 Vol. 27; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
36 MATERIALS SCIENCE
ACTIVATION ENERGY
ALUMINIUM ALLOYS
DEFORMATION
DIFFUSION
DISLOCATIONS
GAS TURBINE ENGINES
INTERMETALLIC COMPOUNDS
MATERIALS
NICKEL ALLOYS
ORIENTATION
SLIP
STRAIN HARDENING
STRAIN RATE
STRAINS
STRESS RELAXATION
STRESSES
TEMPERATURE DEPENDENCE