Effect of iron additions on intergranular cohesion in chromium

The structural, cohesive, and magnetic properties of (111) and (210) tilt grain boundaries (GBs) in pure Cr, and in Cr with Fe additions, are studied from first principles. Different concentration and position of solute atoms are considered. Our calculations show that Fe atoms placed in the GB interstice enhance cohesion, whereas Fe substituted for one of the Cr layer atoms, in most cases, has very small (or negligible) effect on the cohesion at GBs in Cr. We have found that Fe additions show a tendency to enrich the boundaries in Cr. In the presence of Fe additions the magnetic moments on the GB host atoms are substantially modified and those on Fe impurities are reduced. In most cases the moments on Fe additions remain much higher than the local moments on the Cr atoms.