MODELING THERMOPHYSICAL CHARACTERISTICS OF NICKEL-BASED SUPERALLOYS

Thermodynamic processes of phase separation having a substantial effect on the temperature characteristics of nickel superalloys have been modeled. Using an empirical approach, new ratios of the elements K_γ′ and K_γ have been obtained for the fi rst time, accounting for the mutual infl uence of the alloying elements on the temperature of multicomponent compositions of cast superalloys. It has been established that with increase in the ratio K_γ′ there is a rise in critical temperatures and hence, in the thermal stability of the entire system. The calculated values of critical temperatures for ZhS3LS-M and ZMI-3U alloys are in good agreement with experimental ones. Plots have been constructed for the ratio Kγ as a function of the alloying system, and an investigation has been made into the effects of alloying on the liquidus temperature of alloys. Alloying element content ratios are given, as are regression models using which it is possible to predict the width of the temperature interval of crystallization and the optimal temperature of homogenization for a specifi c alloy
   
Author:  A. A. Glotka, S. V. Haiduk, V. Yu. Ol′shanetskii
Keywords:  cast nickel superalloys, thermodynamic processes of phase separation, critical temperatures
Page:  1363