Title:	Hydrogen Traps in Chromium Carbides
DNr:	SNIC 2021/5-478
Project Type:	SNIC Medium Compute
Principal Investigator:	Christina Bjerkén <christina.bjerken@mah.se>
Affiliation:	Malmö universitet
Duration:	2021-11-01 – 2022-11-01
Classification:	10304 20599
Keywords:

Abstract

Hydrogen embrittlement is a common problem for a series of metals leading to decrease in ductility causing crack formation leading to catastrophic failure of the material. The mechanisms of hydrogen embrittlement are complex and still not fully understood. (Barrera O et al. (2018) “Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modelling and design progress from atomistic to continuum.” J Mater Sci 53:6251-6290.) The purpose of this project is to understand hydrogen diffusion in chromium carbide ferrite interfaces. Plane wave density functional theory (PW-DFT) calculations using VASP and OpenMX will be used to calculate binding energies of hydrogen in different bonding sites and position within several chromium carbide lattices. The calculations will focus on the chromium carbide Cr_7 C_3 (space group Pnma). Stable interface structures with ferrite are to be created. Hydrogen diffusion energy barriers will be calculated using the nudge elastic band method (NEB). A more detailed literature overview can be found in Järnkontorets report TO41-44 which is part of the HySteel project. The goal is to gain more information about the influence of chromium carbides on the hydrogen diffusion in ferritic systems.