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In-situ SEM study of slip-controlled short-crack growth in single-crystal nickel superalloy
journal contribution
posted on 2018-11-13, 11:33 authored by Lu Zhang, Liguo Zhao, Anish RoyAnish Roy, Vadim SilberschmidtVadim Silberschmidt, G. McColvinInitiation and growth of short cracks in a nickel-based single crystal were studied by
carrying out in-situ fatigue experiments within a scanning electron microscope
(SEM). Specimens with two different crystallographic orientations, i.e., [001] and [111], were tested under load-controlled tension fatigue in vacuum. Slip-caused crack initiation was identified at room temperature while initiation of a mode-I crack was observed at 650°C. Slip traces continuously developed ahead of the crack tip once initiated and acted as nuclei for early-stage crack growth at both room and high temperature (650°C). These slip traces were caused by accumulated shear deformation of activated octahedral slip systems, which were specifically identified by analysing the surface slip traces and crack-propagation planes. The crack-growth rates were evaluated against stress intensity factor range, revealing the anomaly of slip-controlled short-crack growth. The effects of crystallographic orientations and temperature on fatigue crack growth were subsequently analysed and discussed, including the influence of microstructural features such as carbides and pores.
Funding
The work was funded by the EPSRC (Grant EP/M000966/1 and EP/K026844/1) of the UK and in collaboration with GE Power, Rolls-Royce and dstl.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Published in
Materials Science and Engineering: AVolume
742Pages
564 - 572Citation
ZHANG, L. ... et al., 2019. In-situ SEM study of slip-controlled short-crack growth in single-crystal nickel superalloy. Materials Science and Engineering: A, 742, pp.564-572Publisher
Elsevier (© the authors)Version
- VoR (Version of Record)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/Acceptance date
2018-11-08Publication date
2018-11-09Notes
This paper was published by Elsevier as Gold Open Access with a Creative Commons Attribution (CC BY 4.0) licence.ISSN
0921-5093Publisher version
Language
- en