Atomistic studies of grain boundary segregation in Fe-P and Fe-B alloys—III. Vibrational states of atoms at the grain boundaries

Abstract The local vibrational density of states (LDOS) of segregated impurity and iron atoms at the grain boundaries in α-iron was computed by the recursion method. It is shown that the LDOS's of neighboring iron atoms of segregated phosphorus and boron atoms differ considerably from each other, and the whole shape of LDOS's are closely related to the stress fields around the impurities. All the LDOS's of the iron atoms neighboring a boron atom have sharp peaks in the high frequency region. On the other hand, the LDOS's of certain atoms surrounding a segregated phosphorus impurity atom do not have such peaks. The present results indicate that the segregation of phosphorus atoms at the grain boundaries weaken the bondings between the neighboring iron atoms. This fact is consistent with the calculations of the stress field and electronic structure in papers I and II of this Overview.