Journal article
Application of PAC to study equilibrium point defects in intermetallic compounds
Hyperfine interactions, Vol.80(1), pp.1257-1261
03/1993
Handle:
https://hdl.handle.net/2376/122880
Abstract
A new method has been developed to measure properties of equilibrium, or thermal, defects in intermetallics using the technique of perturbed angular correlations of gamma rays (PAC). After quenching, thermal defects are detected microscopically by distinctive nuclear hyperfine interaction signals produced when they localize next to probe atoms present in high dilution. Using a Schottky defect model and applying the law of mass action to defect equilibria, a linear Arrhenius temperature dependence is predicted for a “normalized” monovacancy site fraction. We have observed such linear dependences in PAC experiments on NiAl, CoAl and TiAl using the111In probe. Features of the method are summarized, of which the most important are the abilities to discriminate between different defects and to determine absolute vacancy concentrations, formation enthalpies and entropies. Extremely large formation entropies have been obtained for NiAl, CoAl and TiAl, suggesting vacancy concentrations of ∼ 15% at the melting temperatures.
Metrics
2 Record Views
Details
- Title
- Application of PAC to study equilibrium point defects in intermetallic compounds
- Creators
- Gary Collins - Washington State UniversityJiawen Fan - Washington State University
- Publication Details
- Hyperfine interactions, Vol.80(1), pp.1257-1261
- Academic Unit
- Physics and Astronomy, Department of
- Publisher
- Springer International Publishing
- Identifiers
- 99900646682301842
- Language
- English
- Resource Type
- Journal article