On the microtwinning mechanism in a single crystal superalloy
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The contribution of a microtwinning mechanism to the creep deformation behaviour of single crystal superalloy MD2 is studied. Microtwinning is prevalent for uniaxial loading along at for the stress range 625 to MPa and for 625 MPa. Using quantitative stereology, the twin fraction and twin thickness are estimated; this allows the accumulated creep strain to be recovered, in turn supporting the role of the microtwinning mode in conferring deformation. Atom probe tomography confirms the segregation of Cr and Co at the twin/parent interface, consistent with the lowering of the stacking fault energy needed to support twin lengthening and thickening. A model for diffusion-controlled growth of twins is proposed and it is used to recover the measured creep strain rate. The work provides the basis for a thermo-mechanical constitutive model of deformation consistent with the microtwinning mechanism.
Date Issued
2017-08-15
Date Acceptance
2017-05-31
Citation
Acta Materialia, 2017, 135 (1), pp.314-329
ISSN
1359-6454
Publisher
Elsevier
Start Page
314
End Page
329
Journal / Book Title
Acta Materialia
Volume
135
Issue
1
Copyright Statement
© 2017 Acta Materialia Inc. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000407536800032&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Technology
Materials Science, Multidisciplinary
Metallurgy & Metallurgical Engineering
Materials Science
Microtwinning
Superalloy
Diffusion
Creep
Segregation
NICKEL-BASE SUPERALLOYS
DIFFUSIONAL DISPLACIVE TRANSFORMATIONS
ELECTRON BACKSCATTER DIFFRACTION
NI-BASED SUPERALLOY
STACKING-FAULT
INTERMEDIATE TEMPERATURES
ACTIVATION-ENERGY
CREEP DEFORMATION
DISLOCATION
PHASE
Publication Status
Published
Date Publish Online
2017-06-05