Effect of electron factor (number of electron holes) on kinetics of nucleation, growth, and dissolution of phases during long-term high-temperature holdings of 0.45C-26Cr-33Ni-2Si-2Nb superalloy

The mechanism of phase transformations that occur in the structure and changes in the phase composition of the cast 0.45C-26Cr-33Ni-2Si-2Nb superalloy held at a temperature of 1150°C for times of up to 100 h have been explained based on a computerized theoretical analysis of the results of experimental investigations. It has been shown that the factor that determines the direction of the process of transformation of the structure (nucleation, growth, and dissolution of various phases) in Fe-Cr-Ni-based alloys during long-term high-temperature holdings is the number of electron holes in the electron shells of chemical elements and the phases they form. Kinetically, the process is limited by the diffusion of a substitutional element with a greatest ratio of its concentration in the new phase to that in the matrix (Cph/C0).