Experimental investigation and thermodynamic modeling of the Ti-V-Zr system

The isothermal sections at 1073 and 1273 K, and liquidus surface projection of the Ti-V-Zr system were investigated using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS) and differential thermal analysis (DTA). Combined with experimental results in the present work and literature, the Ti-V-Zr system was optimized by the means of the CALPHAD (CALculation of PHAse Diagram) method. The solution phases, liquid, hcp (Ti, Zr) and bcc (Ti, V, Zr), were modeled with the substitutional solution model, and the compound V2Zr was treated as (Ti, V, Zr)2(Ti, V, Zr) based on its thermodynamic model in the V-Zr system and the experimental solid solubility of Ti in the Ti-V-Zr system. A set of self-consistent thermodynamic parameters of the Ti-V-Zr system was obtained.