Thermodynamic modeling of the V–Cr–Si system

Abstract

In the present work, an assessment of the V–Cr–Si system was done. Mainly based on previously ternary experimental data on the isothermal section at 1200 °C and on the liquid–solid equilibria, a thermodynamic modeling of the ternary system was performed within the CALPHAD approach using the Thermo-Calc and the Pandat software packages and taking into account data from existing assessment of binary sub-systems. Four intermediate phases were considered as stoichiometric compounds (Cr,V)x(Si)y with substitution of Cr and V at Si ratio constant: (Cr,V)Si, (Cr,V)5Si3, (Cr,V)11Si8 and (Cr,V)6Si5. Two others phases (Cr,V)Si2 and (Cr,V)3Si presenting a slight domain of homogeneity, were described as (Cr,Si,V)1(Cr,Si)2 and (Cr,Si,V)3(Cr,Si,V)1 respectively. The metallic liquid phase and the terminal solid solutions of chromium and vanadium were described by the disordered solutions model as (Cr,Si,V)1(Va)3. The silicon admitting any solubility, its description was limited to (Si). The resulting thermodynamic optimization led to a good agreement with experimental data.