Effects of hydrogen-altered yielding and work hardening on plastic-zone evolution: A finite-element analysis. (17th August 2015)

• Record Type: Journal Article
• Authors: Sasaki, Daisuke; Koyama, Motomichi; Higashida, Kenji; Tsuzaki, Kaneaki; Noguchi, Hiroshi
• Is Part Of: International journal of hydrogen energy. Volume 40:Number 31(2015)
• Page Start: 9825
• Page End: 9837
• Publication Date: 2015-08-17
• Subjects: Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2015.05.187
• Languages: English
• ISSNs: 0360-3199

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Abstract</title> <sec> <p id="abspara0010">In the present paper, finite-element analysis of a cracked specimen was conducted using a unified model for the elastic–plastic deformation and hydrogen diffusion. We considered the effects of the hydrogen-reduced yielding strength and work-hardening coefficient and used a comparison parameter in the simulation of the hydrogen-localized plastic zone near a crack tip. We realized two important facts: (1) the normal component of the plastic strain in the direction of remote stress near the crack tip is significantly increased by the reduced work-hardening coefficient at the same stress-intensity factor; (2) the reduced work-hardening coefficient enhances the localization of the plastic zone when compared to the case using the normal component of the crack-tip plastic strain in the direction of remote stress, which probably determines the ductile–brittle transition of the fatigue-crack propagation mode under a hydrogen atmosphere. These results indicate that the reduction in work-hardening coefficient and the utilization of the crack-tip plastic strain as a parameter to organize the data play important roles in the prediction of the transition condition of hydrogen-accelerated fatigue-crack propagation.</p> </sec> </abstract>