Correlation between geometry and chemistry of a near Σ11 grain boundary

Abstract

A high purity nickel bicrystal was grown using the Chalmers technique. Sulfur microsegregation due to the Gibbs-Thomson effect occurred even at the beginning of ingot solidification owing to the high energy of the intended Σ11 {332} symmetrical grain boundary. Even near the bicrystal seed, the grain boundary misorientation can no longer be described as near Σ11. After determination of the grain boundary parameters in the as-solidified condition, the thin foils underwent a desulfurizing heat treatment. Only when the grain boundary was nearest to Σ11 did the boundary plane become denser, as previously found for Σ11 {311}. The interesting common feature resulting from the thermal desulfurizing treatment was that the grain boundary moved towards a tilt misorientation. This observaton supports the recent calculations indicating that asymmetrical tilt grain boundaries have a lower energy than the asymmetrical twist (or general) grain boundaries.