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Crystallographic analysis for fatigue small crack growth behaviors of a nickel-based single crystal by in situ SEM observation

Authors :
Kai Kadau
Hui-Ji Shi
Changpeng Li
Jialin Gu
Oliver Luesebrink
Yangyang Zhang
Source :
Theoretical and Applied Fracture Mechanics. 69:80-89
Publication Year :
2014
Publisher :
Elsevier BV, 2014.

Abstract

Small fatigue crack growth behaviors of a nickel-base single crystal (SX) are studied by in situ observations with scanning electron microscope (SEM). Two different crack propagation modes are identified, i.e., cracks at room temperature and 300 °C prefer non-crystallographic propagation mode, while those at a higher temperature of 600 °C propagate preferentially along crystallographic slip systems, besides, evident “small crack anomaly” has been partly found. Further computation of crack growth rate reveals that conventional Paris law is found no longer capable of characterizing the crystallographic crack propagation behaviors. Subsequently, with the help of finite element analysis (FEA), the crack tip stress fields are reconstructed and resolved shear stresses in each octahedral slip systems are calculated. It is found that the maximum resolved shear stress intensity parameter, first proposed by Chen and Liu, is able to characterize the growth behaviors of those small cracks.

Details

ISSN :
01678442
Volume :
69
Database :
OpenAIRE
Journal :
Theoretical and Applied Fracture Mechanics
Accession number :
edsair.doi...........f79851ecbe8c748e880327c5135ec10a
Full Text :
https://doi.org/10.1016/j.tafmec.2013.11.002