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Objective. To study the specifics of the distribution of alloying elements in the carbides of the multicomponent system Ni-5Cr-9Co-6Al-1Ti-11.7W-1.1Mo-1.6Nb-0.15C by directional crystallization, using the calculated method of CALPHAD prediction. Research methods. To find regularities and calculate the distribution of alloying elements in the alloy, the latest CALPHAD method was chosen, and modeling of thermodynamic processes of phase crystallization was performed. The obtained results. The results of thermodynamic calculations of the chemical composition of carbides are given in the form of mathematical dependences. The equation of the influence of alloying elements on the dissolution (release) temperature of carbides is obtained. It is shown that the obtained dependences are closely correlated with the thermodynamic processes occurring in the system. Scientific novelty. It is shown that with increasing total concentration of carbide-forming elements, the chemical composition of carbides becomes more complicated. The titanium content of more than 2% leads to an increase in the temperature of the carbide liquidus, and at 4.5 % topologically densely packed phases is formed. When the concentration of molybdenum in the alloy is more than 4%, the probability of precipitating topologically close-packed phases in the structure increases markedly, which negatively affects the mechanical properties and heat resistance. Practical value. Based on an integrated approach for multicomponent heat-resistant nickel-based alloys, new regression models were obtained that allow adequately predict the chemical composition of carbides by the chemical composition of the alloy, which allowed to solve the problem of calculated prediction of carbide composition by chemical composition of the alloy. |
