ALCHEMI of NbCr{sub 2}/V C15-structured Laves phase
- Los Alamos National Lab., NM (United States)
- Oak Ridge National Lab., TN (United States)
Laves-phase intermetallics are of potential interest for use as high temperature structural materials, of which NbCr{sub 2}-based C15- structured Laves phases are particularly attractive. Vanadium-alloyed NbCr{sub 2} Laves phases have been studies. The defect mechanism of a ternary Laves phase is crucial to understanding its physical metallurgy and deformation behavior. It is suggested based on the Nb- Cr-V phase diagram and first-principles total energy and electronic structure calculations for NbCr{sub 2} that V should occupy the B sites in C15-structured AB{sub 2}. In this paper, ALCHEMI is employed to examine this assumption for one composition of a V- alloyed NbCr{sub 2} C15 Laves phase. A Nb-Cr-V alloy of composition Nb{sub 33}Cr{sub 42}V{sub 25} was prepared by arc-melting followed by annealing at 1400{degrees}C for 120 h. Specimens were prepared for microanalysis by cutting 3 mm discs followed by dimpling and ion milling. Energy-dispersive X-ray (EDX) spectra were acquired with a Philips CM30 operating at 300 kV and equipped with a Kevex Quantum detector. Fourteen spectra were collected near <014> over a range of [400] excitations between symmetry and beyond [12 0 0]. Owing to the high accelerating voltage (and therefore relatively flat Ewald sphere) used for these experiments, it was difficult to eliminate non- systematic reflections, although attempts were made to minimize this effect. Spectra were also acquired with a Philips CM12 operating at 120 kV and equipped with an EDAX superUTW detector. Nine spectra were collected near <334> over a range of [440] excitations between symmetry and [880]. Site-distributions were extracted from the data by multivariate statistical analysis (MSA) with delocalization correction as described elsewhere.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 251268
- Report Number(s):
- CONF-960860-8; ON: DE96008621
- Resource Relation:
- Conference: 54. annual meeting of the Microscopy Society of America (MSA): microscopy and microanalysis, Minneapolis, MN (United States), 11-15 Aug 1996; Other Information: PBD: [1996]
- Country of Publication:
- United States
- Language:
- English
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