Thermodynamic Calculation Of Phase Equilibria In Some Co-based Ternary Alloys

The Co-base high-temperature alloys show potential appl(?)ion in the field of aircraft turbines and combustor sections due to their su(?)ior stress-rupture parameters, excellent hot corrosion, good oxidation resistance(?)d thermal fatigue resistance etc.. However, the Co-base high-temperature alloys(?)re just developed recently, and it is difficult to do research on Co-b(?)alloys at high temperatures.Therefore, establishing a complete theoretical syst(?)bty the CALPHAD phase diagram calculation method with the related experim(?) phase diagrams, thermodynamic properties and other related information (?) designing new high-performance Co-based superalloys is of important theoretic(?)alue.In this study, thermodynamic optimization calculations re performed on some Co-based alloys by using the CALPHAD method. The (?)research results consisted of three parts are listed as follows:(1) For the Co-Mo-Cr and Co-Mo-V ternary phase diagr (?) in Co-Mo based system, the corresponding experimental and thermodynamic (?)mation of binary and termery phase diagrams were collected and evaluated, reason(?)le thermodynamic models were established, a set of reasonable thermodynamic pa(?)ters was obtained by using the CALPHAD method, the calculated phase diagr(?)matched with the existing experimental phase diagram very well.(2) For the Co-Nb-W, Co-Cr-W, Co-Cr-Nb and Cr-Nb-in Co-W-Nb-Cr quaternary system, the corresponding experimental and therm(?)amic information of binary and ternery phase diagrams were collected and e(?)uated, reasonable thermodynamic models were established, a set of reason(?)e thermodynamic parameters was obtained by using the CALPHAD method,(?) calculated phase diagram shows great consistent with the existing experimental ph(?)diagram.(3) Based on the thermodynamic parameters of the ten(?)y sub-systems in Co-W-Nb-Cr quaternary system calculated in this work, the Co-W-Nb-Cr quaternary system has been thermodynamically calculated.The cobalt-based alloy thermodynamic models and parameters which was obtained in this study will become part of the high-performance cobalt-based alloy thermodynamic system to provide theoretical guidance for designing and developing the high-performance Co-based alloys.