Positron annihilation spectroscopy of vacancies in Ni/sub 3/Al
Conference
·
OSTI ID:7195526
Lifetime and Doppler-broadening measurements on polycrystalline Ni/sub 3/Al with varying contents of Al(24, 25, and 26 at.%) and boron (0, 100, and 500 wt. ppM) have indicated that small concentrations (of order 10/sup -6/ to 10/sup -5/ at. fraction) of constitutional vacancies are present in nominally stoichiometric and hyperstoichiometric (>25 at.% Al) Ni/sub 3/Al and that boron can precipitate at these vacancies. However, no constitutional vacancies were indicated in hypostoichiometric (<25 at.% Al) Ni/sub 3/Al, and no manifestation of boron precipitation was found. The implications of these results with respect to vacancies in ordered alloys and the problems of synthesizing ductile Ni/sub 3/Al are discussed.
- Research Organization:
- Oak Ridge National Lab., TN (USA); Argonne National Lab., IL (USA)
- DOE Contract Number:
- W-31109-ENG-38; AC05-84OR21400
- OSTI ID:
- 7195526
- Report Number(s):
- CONF-860953-3; ON: DE87002168
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
ANNIHILATION
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BASIC INTERACTIONS
BORON ADDITIONS
BORON ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DOPPLER BROADENING
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
FERMIONS
INTERACTIONS
INTERMETALLIC COMPOUNDS
LEPTONS
LINE BROADENING
NICKEL ALLOYS
NICKEL BASE ALLOYS
POINT DEFECTS
POSITRONS
VACANCIES
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
ANNIHILATION
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BASIC INTERACTIONS
BORON ADDITIONS
BORON ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DOPPLER BROADENING
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
FERMIONS
INTERACTIONS
INTERMETALLIC COMPOUNDS
LEPTONS
LINE BROADENING
NICKEL ALLOYS
NICKEL BASE ALLOYS
POINT DEFECTS
POSITRONS
VACANCIES