The predominant role of strain-induced vacancies in hydrogen embrittlement of steels: Overview

By M. Nagumo, Kenichi Takai. Acta Materialia, 2019

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Abstract Recent studies on hydrogen enhancement of the strain-induced generation of vacancies, i.e. the HESIV mechanism, and its role in hydrogen embrittlement (HE) of steels are overviewed. A high density of vacancies and their clustering have been detected by newly developed low temperature hydrogen thermal desorption spectroscopy and positron lifetime measurements. The promotion of crack nucleation and growth is ascribed to the evolution of damage associated with intense strain localization, and characteristic features of HE such as dependence on the microstructures of steels and test conditions are consistent with the HESIV mechanism. The predominant and supplementary roles of vacancies and hydrogen, respectively, in premature fracture are demonstrated by experiments devised to separate each contribution. A constitutive relation for porous materials is applicable to describe mechanistic effects of the HESIV mechanism on crack growth resistance and strain localization. The sequential void nucleation, growth and link mechanism in nanoscale are suggested.

Subfields: Materials Chemistry, Mechanics of Materials, Metals and Alloys

View Paper: https://www.semanticscholar.org/paper/dbd3598dce1e02d70e689703fd969010ae91397c