Deformation and damage mechanisms during thermal-mechanical fatigue of a single-crystal superalloy

Journal article

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 °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. © 2009 Acta Materialia Inc.

Authors: Moverare, J; Johansson, S; Reed, R

• Publication status: Published
• Journal: ACTA MATERIALIA
• Volume: 57
• Issue: 7
• Pages: 2266-2276
• Publication date: 2009-04-01
• DOI: 10.1016/j.actamat.2009.01.027
• ISSN: 1359-6454
• Language: English
• Keywords: Single crystal superalloy; Thermal mechanical fatigue; Deformation mechanisms; Recrystallization; Twinning