Fatigue Crack Growth Behaviour and Role of Roughness-Induced Crack Closure in CP Ti: Stress Amplitude Dependence

Mansur Ahmed; Md. Saiful Islam; Shuo Yin; Richard Coull; Dariusz Rozumek

doi:10.3390/met11101656

Metals (Oct 2021)

Fatigue Crack Growth Behaviour and Role of Roughness-Induced Crack Closure in CP Ti: Stress Amplitude Dependence

Mansur Ahmed,
Md. Saiful Islam,
Shuo Yin,
Richard Coull,
Dariusz Rozumek

Affiliations

Mansur Ahmed: Department of Mechanical, Manufacturing and Biomedical Engineering, Trinity College Dublin, The University of Dublin, D02 DA31 Dublin, Ireland
Md. Saiful Islam: Department of Glass and Ceramic Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh
Shuo Yin: Department of Mechanical, Manufacturing and Biomedical Engineering, Trinity College Dublin, The University of Dublin, D02 DA31 Dublin, Ireland
Richard Coull: Department of Mechanical, Manufacturing and Biomedical Engineering, Trinity College Dublin, The University of Dublin, D02 DA31 Dublin, Ireland
Dariusz Rozumek: Faculty of Mechanical Engineering, Opole University of Technology, Mikolajczyka 5, 45-271 Opole, Poland

DOI: https://doi.org/10.3390/met11101656
Journal volume & issue: Vol. 11, no. 10
p. 1656

Abstract

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This paper investigated the fatigue crack propagation mechanism of CP Ti at various stress amplitudes (175, 200, 227 MPa). One single crack at 175 MPa and three main cracks via sub-crack coalescence at 227 MPa were found to be responsible for fatigue failure. Crack deflection and crack branching that cause roughness-induced crack closure (RICC) appeared at all studied stress amplitudes; hence, RICC at various stages of crack propagation (100, 300 and 500 µm) could be quantitatively calculated. Noticeably, a lower RICC at higher stress amplitudes (227 MPa) for fatigue cracks longer than 100 µm was found than for those at 175 MPa. This caused the variation in crack growth rates in the studied conditions.

Published in Metals

ISSN: 2075-4701 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Mining engineering. Metallurgy
Website: http://www.mdpi.com/journal/metals

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