Berlin 2018 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 3: Topical session (Symposium MM): Hydrogen in Materials

MM 3.1: Topical Talk

Montag, 12. März 2018, 10:15–10:45, H 0107

Effects of hydrogen on plasticity and fracture in iron—atomic level to mesoscale theory — •Anthony Paxton — King’s College London, London, UK

The phenomenon of hydrogen embrittlement involves processes at all time and length scales. At the smallest scales it must be recognised that the proton in magnetic α-Fe acts as a quantum particle even at room temperature [1]. It is necessary to take into account proton quantum effects if one is not to make errors of factors of two or three in calculations involving trapping and diffusion problems. On the other hand the frequently discussed concepts of hydrogen induced localized plasticity (HELP) and hydrogen enhanced decohesion (HEDE) can only be discussed meaningfully at the mesoscale level and above. Here I will describe our recent work in which we have used magnetic tight binding [2] and density functional theory results as inputs into calculations of dislocation velocity and cohesive strength as functions of stress, temperature and hydrogen concentration in magnetic iron [3, 4]. I may also speculate on certain paradoxes surrounding the theory of elastic shielding of dislocations by hydrogen and on how hydrogen may act to localise plasticity.

1. A. T. Paxton and I. H. Katzarov, Acta Mater., 103, 71 (2016)

2. A. T. Paxton and C. Elsässer, Phys. Rev. B, 82, 235125 (2010)

3. I. H. Katzarov, D. L. Pashov and A. T. Paxton, Phys. Rev. Materials, 1, 033602 (2017)

4. I. H. Katzarov, and A. T. Paxton, Phys. Rev. Materials, 1, 033603 (2017)