Skip to main content
Log in

Application of PAC to study equilibrium point defects in intermetallic compounds

  • Section V: New Developments In Methodology And Experimental Technique
  • Published:
Hyperfine Interactions Aims and scope Submit manuscript

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.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. G.S. Collins, S.L. Shropshire and J. Fan, Hyp. Int. 62 (1990) 1.

    Article  ADS  Google Scholar 

  2. H.-G. Mueller and H. Hahn, Phil. Mag. 50 (1984) 71.

    Article  Google Scholar 

  3. H. Bakker, Mater. Sci. Forum 15–18 (1986) 1155.

    ADS  Google Scholar 

  4. J. Fan, PhD Dissertation, Washington State University, USA (1991).

  5. J. Fan and G.S. Collins, to be published.

  6. J. Fan and G.S. Collins, Proceedings of this conference, Hyp. Int. 78–80 (1993) 745.

    Google Scholar 

  7. B. Lengeler, Phil. Mag. 34 (1976) 259.

    Article  ADS  Google Scholar 

  8. J. Fan and G.S. Collins, Hyp. Int. 60 (1990) 655.

    Article  ADS  Google Scholar 

  9. H.J. Wollenberger, in:Physical Metallurgy, eds. R.W. Cahn and P. Haasen (North-Holland, Amsterdam, 1983) p. 1139.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Collins, G.S., Fan, J. Application of PAC to study equilibrium point defects in intermetallic compounds. Hyperfine Interact 80, 1257–1261 (1993). https://doi.org/10.1007/BF00567488

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00567488

Keywords

Navigation