CUED Publications database

Analysis of thermal desorption of hydrogen in metallic alloys

Raina, A and Deshpande, VS and Fleck, NA (2018) Analysis of thermal desorption of hydrogen in metallic alloys. Acta Materialia, 144. pp. 777-785. ISSN 1359-6454

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Abstract

© 2017 The degree of embrittlement of metallic alloys is sensitive to the concentration of absorbed hydrogen, with hydrogen traps (particularly at grain boundaries) playing an important role. Thermal desorption spectrometry (TDS) is widely used to measure the detrapping and diffusion behaviour of hydrogen in metallic alloys. However, it is problematic to obtain a consistent interpretation of TDS data from the literature, due to the large number of material parameters that influence the measurement, and this results in a wide range of quoted values for trapping parameters such as the number of trap types, trap binding energies and trap densities. In this paper, the governing partial differential equation for hydrogen diffusion with sink and source terms for a single trap is formulated in non-dimensional form, assuming local equilibrium between the hydrogen atoms at the lattice sites and the trap sites. An asymptotic analysis reveals two distinct regimes of diffusion behaviour in TDS tests. Kissinger-type behaviour is expected in a TDS test for low heating rates on an alloy with a low lattice activation energy. Contour maps of maximum hydrogen flux and the corresponding temperature are plotted using axes of trap density and trap binding energy by making use of the full numerical solution (and asymptotic solutions). These maps serve as a useful tool for an accurate and simple determination of the trap binding energy as well as the trap density.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div C > Materials Engineering
Div C > Applied Mechanics
Depositing User: Cron Job
Date Deposited: 20 Dec 2017 20:05
Last Modified: 15 Sep 2020 05:16
DOI: 10.1016/j.actamat.2017.11.011