First principle calculations of impurity segregation in -Fe

Tsuru, Tomohito   ; Suzuki, Chikashi ; Kaji, Yoshiyuki  ; Tsukada, Takashi 

The segregation and clustering of several impurity atoms in -Fe were systematically investigated using first principle calculations with the classical analytical models. The interaction characteristics of Fe and each impurity element can be estimated from the total energy via DFT calculations. Specific clusters that included up to 6 impurity atoms were selected and the free energy changes for clustering were evaluated in verifying the presented evaluation method. The results revealed that interaction parameters of copper and manganese impurities embedded in the -Fe cause a positive value which means that these impurities are poorly soluble in the matrix. Specific confirmation was made that these tendencies were in excellent agreement with the direct calculations of changes in enthalpy for clustering and recent atom probe observations.