Structural, cohesive, and magnetic properties of two symmetric Sigma 3 (111) and Sigma 5(210) tilt grain boundaries (GBs) in pure bcc Fe and in dilute FeCr alloys are studied from first principles. Different concentrations and positions of Cr solute atoms are considered. We found that Cr atoms placed in the GB interstice enhance the cohesion by 0.5-1.2 J/m(2). Substitutional Cr in the layers adjacent to the boundary shows anisotropic effect on the GB cohesion: it is neutral when placed in the (111) oriented Fe grains and enhances cohesion by 0.5 J/m(2) when substituted in the boundary layer of the (210) grains. The strengthening effect of the Cr solute is dominated by the chemical component of the adhesive binding energy. Our calculations show that unlike the free iron surfaces, Cr impurities segregate to the boundaries of the Fe grains. The magnetic moments on GB atoms are substantially changed and their variation correlates with the corresponding relaxation pattern of the GB planes. The moments on Cr additions are two to four times enhanced in comparison with that in a Cr crystal and are antiparallel to the moments on the Fe atoms.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据