Energetics of segregation and embrittling potency for non-transition elements in the Ni 5 (012) symmetrical tilt grain boundary; A First-principles study

Yamaguchi, Masatake   ; Shiga, Motoyuki   ; Kaburaki, Hideo

A series of non-transition elements bound to the Ni 5(012) symmetrical tilt grain boundary (GB) and the (012) free surface (FS) systems has been studied by first-principles calculation using WIEN2k code. The multilayer relaxations in presence/absence of the solutes are determined by the force minimization. The binding energies at some GB/FS/bulk sites including both interstitial and substitutional sites are calculated for all the non-transition elements between H and Rn. The GB/FS segregation energy is obtained by calculating the binding energy difference between the GB/FS site and the bulk site. The embrittling potency energy is obtained by calculating the difference between the GB and FS segregation energies based on Rice-Wang model. Our results show that most of the non-transition elements have negative GB/FS segregation energies. Here, this means that there exists a segregation site in the GB/FS. The embrittling potency energies are positive for most of the solutes. However, some exceptions like Be, B, C, and Si having negative and large embrittling potency can enhance the GB cohesion. Our results are found to be consistent with the experimental findings.