Effect of boron on grain-broundaries in Ni3Al
Journal Article
·
· Acta Metall.; (United States)
The effects of boron concentration, alloy stoichiometry, and microstructure on the strength and ductility of Ni3Al containing 24 and 26 at. pct Al are investigated. The ductility and fracture behavior of B-doped Ni3Al, which depend on deviation from alloy stoichiometry, are characterized by tensile tests at room temperature, and are correlated with grain boundary chemistry and structure features as determined by Auger electron spectroscopy, SEM, and TEM. With a decrease in aluminum content of B-doped Ni3Al below 25 at. pct, the ductility increases dramatically and there is a change in fracture mode from intergranular to transgranular. It is shown that the level of boron segregated to grain boundaries increases and that the amount of grain-boundary aluminum decreases with decreasing bulk aluminum concentration. Boron also has a tendency to segregate to the grain boundaries but not to cavity surfaces, whereas sulfur demonstrates the opposite behavior. The results are in agreement with existing theories of solute segregation effects on grain-boundary cohesion. It is also shown that annealing treatment at 1000/sup 0/C results in an increase in grain size and a decrease in yield strength. 58 references.
- Research Organization:
- Oak Ridge National Lab., TN
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5387346
- Journal Information:
- Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 33; ISSN AMETA
- 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
ANNEALING
BORON ADDITIONS
BORON ALLOYS
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
FRACTURE MECHANICS
GRAIN BOUNDARIES
GRAIN SIZE
HEAT TREATMENTS
MECHANICAL PROPERTIES
MECHANICS
MICROSTRUCTURE
NICKEL ALLOYS
SIZE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
ANNEALING
BORON ADDITIONS
BORON ALLOYS
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
FRACTURE MECHANICS
GRAIN BOUNDARIES
GRAIN SIZE
HEAT TREATMENTS
MECHANICAL PROPERTIES
MECHANICS
MICROSTRUCTURE
NICKEL ALLOYS
SIZE