Chemomechanical Origin of Hydrogen Trapping at Grain Boundaries in FCC Metals

Abstract

Hydrogen embrittlement of metals is widely observed, but its atomistic origins remain little understood and much debated. Combining a unique identification of interstitial sites through polyhedral tessellation and first-principles calculations, we study hydrogen adsorption at grain boundaries in a variety of face-centered cubic metals of Ni, Cu, gamma-Fe and Pd. We discover the chemomechanical origin of variation of adsorption energetics for interstitial hydrogen at grain boundaries. A general chemomechanical formula is established to provide accurate assessments of hydrogen trapping and segregation energetics at grain boundaries, and it also offers direct explanations for certain experimental observations. The present study deepens our mechanistic understanding of the role of grain boundaries in hydrogen embrittlement, and promises a viable path towards predictive microstructure engineering against hydrogen embrittlement in structural metals.

Cited by in corpus (8)

• Hydrogen bubble nucleation by self-clustering: Density Functional Theory and statistical models studies using tungsten as a model system
• Five Degree-of-Freedom Property Interpolation of Arbitrary Grain Boundaries via Voronoi Fundamental Zone Octonion Framework
• Describe, Transform, Machine Learning: Feature Engineering for Grain Boundaries and Other Variable-Sized Atom Clusters
• Grain boundary interstitial segregation in substitutional binary alloys
• Hydrogen clustering in bcc metals: atomic origin and strong stress anisotropy
• Combined effects of nonmetallic impurities and planned metallic dopants on grain boundary energy and strength
• Atomistic understanding of hydrogen bubble-induced embrittlement in tungsten enabled by machine learning molecular dynamics
• Uncovering the influence of common nonmetal impurities on the stability and strength of a $\Sigma$5 (310) grain boundary in Cu