Title:	Hydrogen Traps in Chromium Carbides
DNr:	SNIC 2020/5-537
Project Type:	SNIC Medium Compute
Principal Investigator:	Christina Bjerkén <christina.bjerken@mah.se>
Affiliation:	Malmö universitet
Duration:	2020-10-28 – 2021-11-01
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 investigate possible hydrogen binding sites in chromium carbide. 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 three stable chromium carbide structures, namely the cubic 〖Cr〗_23 C_6 (space group Fm3 ̅m), the orthorhombic Cr_3 C_2 (space group Pnma) and Cr_7 C_3 (space group Pnma) structures. A more detailed literature overview can be found in Järnkontorets report TO41-44 which is part of the HySteel project. The goal is to identify H-traps within chromium carbide and determine their size.