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Influence of notch root radius on high cycle fatigue properties and fatigue crack initiation behavior of Ti-55531 alloy with a multilevel lamellar microstructure

Authors :
Zhong Zhang
Chaowen Huang
Zilu Xu
Jiang Yang
Shaolei Long
Changsheng Tan
Mingpan Wan
Dan Liu
Shengli Ji
Weidong Zeng
Source :
Journal of Materials Research and Technology, Vol 24, Iss , Pp 6293-6311 (2023)
Publication Year :
2023
Publisher :
Elsevier, 2023.

Abstract

Notch high cycle fatigue (HCF) properties and microcrack initiation behavior of Ti-55531 alloy with a multilevel lamellar microstructure under various notch radii were systematically investigated. Results indicate that the reduction of notch root radius significantly promotes fatigue microcrack initiation, and then dramatically reduces the HCF life and strength of the alloy. Cyclic deformation of the alloy is mainly controlled by the slipping and deformation twinning in α plates. The primary fatigue crack initiation micro-mechanism is α/β interface cracking induced by slipping and twinning at all notch HCF specimens. Moreover, the volume fraction of twinning would increase with decreasing of the notch root radius. Interestingly, when the notch root radius is the smallest (R = 0.14 mm) and the stress concentration factor is the largest (Kt = 4), in addition to slipping and twinning, basal stacking faults promoting the cracking of α/β interface could be another crucial HCF microcrack initiation mechanism of the alloy. Furthermore, with decreasing of notch root radius and increasing of stress concentration factor, the size of cycle plastic deformation zone at notch root gradually reduces to the size of α colony and even the α plate. Therefore, the order of influential degree of three different levels microstructure on the crack initiation mechanism of notched HCF can be arranged as α plate > α colony > β GB.

Details

Language :
English
ISSN :
22387854
Volume :
24
Issue :
6293-6311
Database :
Directory of Open Access Journals
Journal :
Journal of Materials Research and Technology
Publication Type :
Academic Journal
Accession number :
edsdoj.034aa8ec6da048798fb6757caa40523a
Document Type :
article
Full Text :
https://doi.org/10.1016/j.jmrt.2023.04.211