Directional coarsening in nickel-base single crystals with high volume fractions of coherent precipitates

Journal Article · Wed Jun 01 04:00:00 EDT 1994 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(94)90011-6· OSTI ID:7087161

Pollock, T M; Argon, A S ^[1]

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1. Massachusetts Inst. of Technology, Cambridge, MA (United States)

Directional coarsening has been investigated experimentally in two nickel-base single crystal alloys with high volume fractions of precipitates. The initial elastic stresses due to the positive or negative misfit of the coherent precipitates biased the orientation of the precipitates developed during coarsening. However, directional coarsening of the precipitates did not occur until some limited amount of creep deformation was initiated. With the application of an external stress, dislocations penetrated preferentially into the most highly stressed matrix channels and directional coarsening occurred by coalescence of the [gamma][prime] precipitates in the plane of the initially less highly stressed channels, where the misfit stresses were not altered by the presence of misfit relieving dislocations. The diffusional processes responsible for rafting apparently operate on the local scale of the precipitates, with preferential local dissolution of the [gamma][prime] and diffusional flow of alloying elements around the periphery of the precipitates.

• OSTI ID: 7087161
• Journal Information: Acta Metallurgica et Materialia; (United States), Journal Name: Acta Metallurgica et Materialia; (United States) Vol. 42:6; ISSN 0956-7151; ISSN AMATEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
CREEP
CRYSTALS
DATA
DEFORMATION
EXPERIMENTAL DATA
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
INFORMATION
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
MONOCRYSTALS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NUMERICAL DATA