Thermodynamic Calculation Of Some Important Ternary Phase Diagrams In Nickel-based Superalloys

Nickel-based superalloys are widely used in aircraft engines due to their excellent overall performance at medium and high temperatures.Due to the fact that there are more than ten elements in nickel-based superalloys,relying on a large number of experimental methods to develop nickel-based alloy materials meeting the performance requirements will cost enormous human,financial and material resources.The phase diagram is called the "map" of the material design.It is necessary to master the related phase diagrams and thermodynamic information for the better design of the nickel-based superalloy material.The thermodynamic calculation of the phase diagram of the nickel-based superalloy and the establishment of a thermodynamic database for the nickel-based superalloy are of great theoretical value for the design of the nickel-based superalloy.In this study,thermodynamic assessments of some important nickel-based superalloy ternary system phase diagrams were carried out using the CALPHAD method.Major research contents are listed as follows:1.Based on the relevant experimental information,the Nb-Si-X(X:Ta,V)ternary system has been assessed by using CALPHAD method.Calculated isothermal section diagrams at 1100?,1200? and 1300?in comparison with experimental data of the Nb-Si-Ta and Nb-Si-V two ternary system and calculated some vertical section.2.Based on the relevant experimental information,the Hf-V-X(X:Nb,Ti)ternary system has been assessed by using CALPHAD method.Calculated isothermal section diagrams at 1100? and 1300? in comparison with experimental data of the Hf-V-Nb and Hf-V-Ti two ternary system.The thermodynamic model of the ternary phase Hf0.4Nb0.4V0.2 in the Hf-V-Nb ternary system is defined as.3.Based on the relevant experimental information from our group,the Cr-Re-X(X:Nb,Ti)ternary system has been assessed by using CALPHAD method.Calculated isothermal section diagrams at 1100? and 1200? in comparison with experimental data of the Cr-Re-Mo and Cr-Re-Ru two ternary system.Calculated the diagrams of the Cr-Re binary system with addition of a small amount of Mo,Ru.