Grain boundaries in Ni sub 3 Al. 2; The dislocation structure of small angle boundaries

Journal Article · Wed Jan 01 04:00:00 EST 1992 · Acta Metallurgica; (United States)

OSTI ID:7306750

Kung, H; Sass, S L ^[1]

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1. Cornell Univ., Ithaca, NY (United States). Dept. of Materials Science and Engineering

This paper discusses the dislocation structure of small angle tilt and twist boundaries in ordered Ni{sub 3}Al, with and without boron, investigated using transmission electron microscopy. Dislocation with Burgers vectors that correspond to anti-phase boundary (APB)-coupled superpartials were found in small angle twist boundaries in both boron-free and boron-doped Ni{sub 3}Al, and a small angle tilt boundary in boron-doped Ni{sub 3}Al. The boundary structures are in agreement with theoretical models proposed by Marcinkowski and co-workers. The APB energy determined from the dissociation of the grain boundary dislocations was lower than values reported for isolated APBs in Ni{sub 3}Al. For small angle twist boundaries the presence of boron reduced the APB energy at the interface until it approached zero. This is consistent with the structure of these boundaries containing small regions of increased compositional disorder in the first atomic plane next to the interface.

• OSTI ID: 7306750
• Journal Information: Acta Metallurgica; (United States), Journal Name: Acta Metallurgica; (United States) Vol. 40:1; ISSN 0001-6160; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360103 -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
BORON ADDITIONS
BORON ALLOYS
BURGERS VECTOR
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
DISLOCATION PINNING
ELECTRON MICROSCOPY
GRAIN BOUNDARIES
MICROSCOPY
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
ORDER-DISORDER TRANSFORMATIONS
PHASE TRANSFORMATIONS
TRANSMISSION ELECTRON MICROSCOPY