LAUSR

Abstract To study the precipitation reactions, homogenization of the as-cast structure, thermomechanical processing, and high-temperature creep of superalloys, understanding the interdiffusion parameters of alloying elements is a vital requirement. This requires consistent diffusion parameters, which should be obtained by one technique. Accordingly, in the present work, based on the concept of residual segregation index during homogenization treatment of as-cast Inconel 718 superalloy, the activation energy (Q) for interdiffusion of Nb, Mo, Cr, Ti, and Fe were determined as ~ 232, 286, 276, 256, and 280 kJ/mol, respectively. Moreover, the pre-exponential constant (D0) for Nb, Mo, Cr, Ti, and Fe were determined as 0.0037, 0.288, 0.283, 0.0430, and 0.31 cm2/s, respectively. Based on these results, the diffusion coefficient of Mo in austenite was found to be the lowest value, which was consistent with the fact that the diffusion of Mo is the controlling micro-mechanism of homogenization.