Theoretical study of the substitutional solute effect on the interstitial carbon in nickel-based alloy

The carbon binding in nickel-based alloy with 3d, 4d and 5d transition metal solutes is investigated by using first-principles methods. The first nearest neighbor carbon exhibits repulsive behaviors with most metals except Cr element, which are analyzed from both mechanical and chemical aspects. It shows that the size factor from metal solute is one of the main reasons affecting 1NN carbon-metal binding. Further electronic structures analysis shows that the hybridization of C 2p(z)-M 3d(z)(2) states plays an important role in C-M bonding. The introduced vacancy enhances carbon bonding to most metal solutes through local strain change and charge redistribution. Among all the metal solutes, Cr shows its affinity to carbon which coincides with the previous experimental observation that chromium carbides are commonly precipitated in nickel-based alloys. The present study helps to understand the carbon-metal solute interaction in nickel-based alloys.