Abstract
The deformation and damage mechanisms arising during thermal mechanical fatigue (TMF) of the single-crystal superalloy CMSX-4 have been investigated, both in the virgin condition and after long-term exposure at 1000 degrees C. Fundamental differences in the mechanical response due to ageing have been discovered, which are attributed to the tendency for the precipitation of topologically close-packed phases during deformation. In the virgin condition, the deformation during TMF is very localized and concentrated to twin bands which extend over the complete cross-section of the specimen; at the interception of these bands, the material is prone to recrystallization. The aged material on the other hand shows a much more dispersed deformation behaviour in which the length and thickness of the twins are much smaller and no recrystallization is found. Instead, significant local misorientations-implying crystal rotation are observed in the aged material after rupture. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Original language | English |
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Pages (from-to) | 2266-2276 |
Number of pages | 11 |
Journal | Acta Materialia |
Volume | 57 |
Issue number | 7 |
DOIs | |
Publication status | Published - 1 Apr 2009 |
Keywords
- Recrystallization
- Deformation mechanisms
- Thermal mechanical fatigue
- Twinning
- Single crystal superalloy