A Phase-field model for simulating hydrogen-induced pitting corrosion with solid-solid phase transformation in the metal

TL;DR

This paper introduces a phase-field model to simulate hydrogen-induced pitting corrosion in metals, capturing complex mechanisms like solid-solid phase transformation and mechanical interactions, validated on uranium with realistic surface bulges.

Contribution

The work presents a novel phase-field model and numerical method that incorporate elastic strain energy and free boundary conditions to simulate anisotropic pit morphology and surface bulges.

Findings

Successfully simulates anisotropic pit morphology with surface bulges.

Reveals compression of uranium and dilation of hydride during corrosion.

Aligns simulation results with experimental observations.

Abstract

Hydrogen-induced pitting corrosion of metallic is a common phenomenon that damages the integrity and durability of the materials. Its numerical simulation is still a challenge due to many complex mechanisms, especially solid-solid phase transformation and mechanical interaction, leading to the anisotropic growth of hydride and inducing some bulges on the metal surface. In our work, we propose a phase-field model and numerical technique for simulation of hydrogen-induced pitting corrosion, and apply it to the system of $\alpha$-Uranium. In our model, the elastic strain energy is introduced to approximate the anisotropic pit morphology induced by the mechanical interaction between metal and hydride. For the numerical technique, the free boundary condition based on the finite element method is adopted to introduce the bulges of the metal surface. By the application of our model and numerical technique, the anisotropic pit morphology with a bulge on the metal surface in agreement with experiments of $\alpha$-Uranium is obtained. Moreover, the compression of $\alpha$-Uranium and the dilation of its hydride are discovered, which develops the deep understanding of hydrogen-induced pitting corrosion. This model is expected to be applied to the health detection of hydrogen-induced pitting corrosion of metal in the industry.