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Crystal-plasticity finite-element modelling of cyclic deformation and crack initiation in a nickel-based single-crystal superalloy under low-cycle fatigue

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journal contribution
posted on 20.07.2020 by Lu Zhang, Liguo Zhao, Rong Jiang, Chris Bullough
Nickel‐based single‐crystal superalloys are predominantly used for turbine blades in aircraft engines and land‐based gas turbines. Understanding and predicting the fatigue failure of Ni‐based single‐crystal superalloys are critical to ensure the safety of these components during operation. In this paper, low‐cycle fatigue experiments were carried out to investigate cyclic deformation of a nickel‐based single‐crystal superalloy MD2, recently developed by GE Power, with different crystallographic orientations. Specialty in situ scanning electron microscope (SEM) tests were also conducted to study the slip‐controlled initiation of short cracks under low‐cycle fatigue. In particular, the stress–strain response for both [001] and [111] orientations was used to calibrate a crystal plasticity model, which allowed us to simulate the activation of crystallographic slip systems and predict the initiation of short fatigue crack. Using the accumulated shear strain as a criterion, the simulations confirmed that the slip system with the maximum accumulated shear strain appeared to control the crack initiation. The location and direction of slip traces and short cracks, captured by the crystal plasticity finite‐element simulations, agreed with the in situ SEM observations. The modelling tool will be valuable for assessing the structural integrity of critical gas turbine blades.

Funding

Oxidation Damage at a Crack Tip and its Significance in Crack Growth under Fatigue-Oxidation Conditions : EP/K026844/1

Dislocation-Microstructure Interaction at a Crack Tip - In Search of a Driving Force for Short Crack Growth : EP/M000966/1

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

Fatigue and Fracture of Engineering Materials and Structures

Volume

43

Issue

8

Pages

1769-1783

Publisher

Wiley

Version

VoR (Version of Record)

Rights holder

© The Authors

Publisher statement

This is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Acceptance date

20/03/2020

Publication date

2020-04-13

Copyright date

2020

ISSN

8756-758X

eISSN

1460-2695

Language

en

Depositor

Prof Liguo Zhao Deposit date: 20 March 2020

Licence

Exports