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Modelling crack-tip behaviour in a directionally solidified nickel alloy under fatigue-oxidation conditions

conference contribution
posted on 27.02.2020, 10:08 by RJ Kashinga, Liguo ZhaoLiguo Zhao, Vadim SilberschmidtVadim Silberschmidt
A finite-element approach, to study crack-tip behaviour for a directionally solidified nickel-based superalloy subjected to high-temperature fatigue loading in vacuum and air, is presented. In vacuum, crack-tip behaviour was entirely controlled by mechanical deformation, hence, a criterion based on accumulated plastic strain was sufficient to describe damage. In air, effects of oxidation on crack-tip deformation were studied using a diffusion-based approach; further developed to investigate a synergetic interaction between fatigue loading and oxygen penetration. Stress-assisted diffusion and dilatation from oxygen penetration into a crack tip, were considered. A local compressive stress induced by oxygen penetration compensated part of the tensile stresses from mechanical loading. To predict crack growth rate under fatigue-oxidation conditions, a two-parameter crack-growth criterion, based on accumulated plastic strain and oxygen concentration at the crack tip, was developed. Obtained numerical results compared well with experimental data in the literature.

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

Advances in Engineering Materials, Structures and Systems: Innovations, Mechanics and Applications - Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation (SEMC 2019), September 2-4, 2019, Cape Town, South Africa

Pages

437 - 442

Source

7th International Conference on Structural Engineering, Mechanics and Computation (SEMC 2019)

Publisher

Taylor & Francis

Version

VoR (Version of Record)

Rights holder

© Taylor & Francis Group, London

Publication date

2019-08-21

Copyright date

2019

ISBN

9781138386969

Language

en

Editor(s)

Alphose Zingoni

Location

Cape Town, South Africa

Event dates

2nd September 2019 - 4th September 2019

Depositor

Prof Liguo Zhao. Deposit date: 26 February 2020