Hydrogen-assisted microcrack formation in bearing steels under rolling contact fatigue. (May 2020)

• Record Type: Journal Article
• Authors: Liang, X.Z.; Zhao, G.-H.; Owens, J.; Gong, P.; Rainforth, W.M.; Rivera-Díaz-del-Castillo, P.E.J.
• Is Part Of: International journal of fatigue. Volume 134(2020)
• Publication Date: 2020-05
• Subjects: Hydrogen embrittlement -- Rolling contact fatigue -- Crack propagation; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2020.105485
• Languages: English
• ISSNs: 0142-1123

Abstract

Highlights: H induces voids and cracks at grain boundaries during rolling contact fatigue. Mixed H embrittlement mechanism: localised plasticity and intergranular debonding. Quantitative proof of increased void and crack populations upon H ingress. Abstract: A ball-on-rod RCF tester was employed to investigate the failure mechanisms of hydrogen-rich rolling components. The formation of defects, voids and surface cracks is significantly facilitated in hydrogen-rich bearing steels. In samples with RCF cycles of 1.6 × 10 7, the void density in hydrogen-rich samples is about three times that of hydrogen-free samples, whilst their crack length density four times that of hydrogen-free samples. This is due to a higher stress intensity factor around inclusions which is altered by hydrogen. Further characterisation confirms that grain boundaries are preferential sites for void formation and crack propagation.