A Thermodynamic Model for Thermomigration in Metals

Abstract

We investigate the mechanisms involved in the thermomigration of interstitial hydrogen in metals. Using irreversible thermodynamics, we develop a comprehensive mechanistic model to capture the controlling effects. Crucially, through validation against published experimental data, our results demonstrate that an electron-wind effect plays a significant role, particularly for materials in which the thermomigration direction matches the heat flux. These findings provide new insights into the factors that affect the localisation of solutes in metals. Moreover, our results indicate that atomistic models may be inadequate for detailed thermomigration studies due to the omission of electronic effects.

Figures (2)

• Figure 1: A comparison of the predicted temperature-dependence of the heat of transport using our mechanistic model derived from the $\boldsymbol{X}_{\mathrm{H}}$ driving force (shown in black) and the CALPHAD-based model (shown in red) with experimental data from Gonzalez and Oriani GONZALEZ1965 for Fe and Ni. Continuous lines represent predictions in Fe and dashed lines represent predictions in Ni.
• Figure 2: Validation of the revised heat of transport model, accounting for the electron-wind effect by comparison with experimental data from Gonzalez and Oriani GONZALEZ1965 for (a) Fe and (b) Ni. Dashed lines represent individual contributions to the total heat of transport.