Morphology, crystallography and kinetics of sympathetic nucleation
The phenomenon of sympathetic nucleation was investigated, employing the Widmanstatten ..cap alpha.. precipitation in Ti-6.6 at%Cr and Ti-8.6 at%Mn alloys as a typical example. Two types of morphological arrangement, resulting from edge-to-edge and edge-to-face sympathetic nucleation are identified. The question of whether the latter arrangement is formed by branching in the style of solidification dendrities is considered. By expressing the orientation relationship of precipitates in the form of a matrix, a search was made for the relationships which permit branching with equivalent pairs of conjugate habit planes. From the results of such analyses, carried out on commonly observed orientation relationships among f.c.c., b.c.c. and h.c.p. phases, it is concluded that crystallographic constraints essentially prohibit branching in all of these systems. A comparative theoretical study of the relative nucleation kinetics of homogeneous, grain boundary and sympathetic nucleation.
- Research Organization:
- Naval Chemical and Metallurgical Lab., Naval Dockyard, Tiger Gate, Bombay 400 023
- OSTI ID:
- 5524907
- Journal Information:
- Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 35:3; ISSN AMETA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
BCC LATTICES
CHEMICAL REACTION KINETICS
CHROMIUM ALLOYS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALLOGRAPHY
CRYSTALS
CUBIC LATTICES
DENDRITES
FCC LATTICES
GRAIN BOUNDARIES
HCP LATTICES
HEXAGONAL LATTICES
KINETICS
MANGANESE ALLOYS
MICROSTRUCTURE
MORPHOLOGY
NUCLEATION
PHASE TRANSFORMATIONS
PRECIPITATION
REACTION KINETICS
SEPARATION PROCESSES
SOLIDIFICATION
STRUCTURAL CHEMICAL ANALYSIS
TITANIUM ALLOYS