Fe-3wt%Si固溶体双結晶の粒界移動

Abstract

The migration kinetics of sigma9, sigma51 and low angle tilt boundaries in Fe-3wt%Si solid solution bicrystals was experimentally studied at temperatures between 1200 and 1625K by a capillarity technique. The driving force and the mobility of the grain boundary migration were calculated from the experimental results. On the basis of the calculations, the mechanism of grain boundary migration was discussed. There are two different mechanisms of grain boundary migration. At low temperatures, the activation energy of the grain boundary migration coincides with that of the intrinsic diffusion of Si in alpha-Fe. The rate controlling process of grain boundary migration seems to be the dragging of solute atmosphere formed along the migrating grain boundary. On the other hand, at high temperatures, the activation energy of the grain boundary migration is about 2/3 of that of the self diffusion in alpha-Fe. Therefore, the grain boundary migration at these temperatures is considered to be controlled by the grain boundary diffusion.