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Hyperfine Interactions

, Volume 60, Issue 1–4, pp 655–658 | Cite as

Point defects in NiAl near the equiatomic composition

  • Jiawen Fan
  • Gary S. Collins
Article

Abstract

Perturbed γ-γ angular correlation spectroscopy was applied to study the structure and properties of point defects near111In probes in quenched and annealed NiAl samples with five compositions in the range cNi=48–52%. Quadrupole interaction signals are analysed in terms of near-neighbor Ni-vacancy and nextnear-neighbor Ni antisite atom defects. Large mono- and divacancy concentrations were observed in all samples after quenching. For cNi<50%, the vacancy defects could not be annealed out (structural defects). For CNi>50%, large quenched-in vacancy concentrations annealed out near 500°C. For cNi=50%, most vacancies annealed out near 500°C, but about 35% of the111In probes retained a trapped monovacancy. This is attributed to a very low value of the formation enthalpy of a vacancy next to the In probe, estimated to be 0.16(2) eV. A lesser annelaing stage detected at 300°C is tentatively attributed to diffusion of Al-vacancies.

Keywords

Enthalpy Structural Defect NiAl Point Defect Correlation Spectroscopy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© J.C. Baltzer A.G., Scientific Publishing Company 1990

Authors and Affiliations

  • Jiawen Fan
    • 1
  • Gary S. Collins
    • 1
  1. 1.Department of PhysicsWashington State UniversityPallmanUSA

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