Thermodynamic Descriptions of the Co–Zr and Co–Fe–Zr Systems

Abstract

The Co-Fe-Zr system and its Co-Zr subsystem were optimized using the CALculation of PHAse Diagram (CALPHAD) approach. The substitutional solution model was used for describing the phases liquid, fcc_A1, bcc_A2 and hcp_A3. Two Laves phases were modeled as (Co,Fe,Zr) 2 (Co,Fe,Zr) 1 , and the phases CoFe and CoZr with the bcc_B2 crystal structure were described as the ordered one of bcc_A2 in the formula (Co,Fe,Va,Zr) 0.5 (-Co,Fe,Va,Zr) 0.5 Va 3 . With limited solubility ranges, all other phases were treated as the line compounds (Co,Fe) m Zr n . An excellent agreement between the reported and calculated results was reached. The reliable thermodynamic parameters of the Co-Fe-Zr system were acquired, which can be well applied to various thermodynamic calculations and materials design.