On the Coupling of Mass Diffusion and Non-Mechanical Energy Flow in Metals under Finite Deformation~!2008-03-24~!2008-06-02~!2008-06-12~!

Abstract

Abstract:The governing equation of non-mechanical energy flow in metals, undergoing finite deformation, is presented. The coupling of non-mechanical energy flow, mass diffusion and metal elastic-plastic deformation is rigorously taken into account. The analysis is particularly useful in cases of diffusion-driven degradation mechanisms ahead of stationary cracks or cracks initiating growth, under temperature variations.

On the Precipitation of Hydrides in Metals under Stress - Finite Deformation Approach

“…It is shown that hydrostatic stress strongly influences hydrogen terminal solid solubility, which agrees with experimental observation on position of hydride precipitation ahead of a mode-I blunted crack and on direction of crack growth. The present analysis is complementary to previous papers on mass diffusion and non-mechanical energy flow in metals under finite deformation [12,13] and it is expected to facilitate hydride induced embrittlement studies under conditions, which require finite deformation approach.…”

“…Therefore, a finite deformation approach is necessary for the detailed simulation of a crack growth step, which involves the simultaneous operation of the coupled processes of hydrogen diffusion, hydride precipitation, non-mechanical energy flow, mainly in the presence of temperature gradient as in nuclear industry applications, and material deformation. In previous papers, the governing equations for mass diffusion and non-mechanical energy flow in metals, under finite deformation, were presented [12,13]. In the present work, the terminal solid solubility of hydrogen in a metal is derived by employing finite deformations.…”

“…When the metal deforms plastically too, then F a is set equal to the elastic part of the deformation gradient (e.g. [13]) and the reference configuration is produced by applying the mapping F a 1 on the deformed configuration, where a is applied.…”

“…Thus, a tool for predicting hydride precipitation is provided. In other words, the present relation of hydrogen terminal solid solubility, together with the governing equations for hydrogen diffusion and nonmechanical energy flow in [12,13], can be part of a finite element algorithm, based on finite deformation, for the detailed simulation of delayed hydride cracking.…”