Structure Diagnostic of Iron-Based Out-of-Peritectic Alloys during Nonequilibrium Crystallization

Abstract

The effect of the contribution of basic components (silicon, manganese, chromium, and nickel) in multicomponent iron-based alloys on critical point position of the peritectic reaction was studied by using the POLYTHERM software package. Obtained temperature and concentration values of critical points of peritectic transformation, depending on the content of iron-based alloy components (Si, Mn, Cr, Ni) were used to build summary equations, represented the change in temperature and concentration of critical points by variation of binary, ternary and quaternary alloy composition. Investigation of nonequilibrium crystallization of out-of-peritectic casting steels was performed by using a system of computer models describing thermodynamic, thermophysical, diffusion and capillary processes during solidification under coalescence of dendritic branches. The nonequilibrium crystallization regime was specified by suppression of diffusion in the solid phase, reflected by adding the inverse diffusion parameter to the system of the computer model. The application of these computer models not only allows to make calculations of the temperature course, the solid phase fraction and the composition of the components in the liquid phase but also the calculation of secondary arm spacing during crystallization with taking into account the coalescence process.