Phase field study for the influence of shell potential to Cr substitute behavior in Ni₇₅Al₁₅Cr₁₀

The effects of the Cr substitutional behavior in the different third and fourth nearest interactive potential is studied by the phase field method in Ni₇₅Al₁₅Cr₁₀ at temperature 873 K. The results show: the evolution of the Cr long range order parameter demonstrates the existence of Cr's substitution for both Ni and Al sites in L1₂ type ordered structure, and whose solubility in γ′ phase is opposite between the third and fourth shell potential. Besides that, with the increase of the Ni-Al, Ni-Cr third nearest pairwise potential, the occupation of Cr at α sublattice sites enhance while β site's occupation falls down, but for the Ni-Al, Ni-Cr third nearest pairwise potential, this tendency reverse. As the Al-Cr third pairwise potential increase, the Cr occupation at α and β sites increase. Otherwise the increase of the Al-Cr fourth nearest pairwise potential promotes Cr's substitution for the Ni sites and decrease Cr's substitution for Al sites.