Study on the isothermal section at 1373K in the Fe-Mo-V system and atomic mobility of the V-rich bcc phase

To determine the homogeneity range of the bcc phase in the Fe-Mo-V system, the isothermal section of the Fe-Mo-V system at 1373 K was constructed by analyzing phase constituents of annealing samples using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Two groups of diffusion couples A and B with the terminal alloys located in the V-rich bcc phase region were prepared and annealed at 1473 K for 96 h and 1373 K for 288 h, respectively. Based on the obtained concentration profiles, the ternary diffusion behaviors of the V-rich bcc phase in the Fe-Mo-V alloys were investigated by the electron probe microanalysis (EPMA) technique combined with the Whittle and Green method. Depending on DICTRA software, the atomic mobility parameters for the bcc phase of the Fe-Mo-V system were optimized. The experimental concentration profiles and diffusion paths in the Fe-Mo-V alloys can be well reproduced using the atomic mobility and thermodynamic parameters.