Executive Summary : | The research focuses on developing new alloys that can increase the operating temperatures of Ni-base superalloys. High-entropy super alloys (HEsAs) and refractory high entropy superalloys (RHEsAs) are promising due to their combination of critical properties. However, more critical design and experimental investigations are needed to enable their application. The elements in these alloys are typically Ni, Al, Co, Cr, Fe, Mo, Nb, Ta, Ti, V, W, and Zr. The Calphad method, which minimizes Gibbs energy, is used for effective alloy design. However, reliable thermodynamic descriptions for Al-Cr-Mo and Al-Cr-W are missing, leading to inaccuracies in Calphad-based alloy design. The proposed work aims to perform thermodynamic assessments for Al-Cr-Mo and Al-Cr-W ternary systems to generate reliable Gibbs energy descriptions. This will be achieved through phase equilibration experiments, diffusion couple measurements, calorimetry studies, ab-initio calculations, isothermal annealing at several temperatures for a long time, and high resolution transmission electron microscopy (HRTEM) for representative samples. The Calphad critical assessment of input thermodynamic and phase equilibria data and statistical fitting technique for Gibbs energy optimization will also be assessed. The expected output and outcome of the proposal include the thermodynamic description of Al-Cr-Mo and Al-Cr-W systems, research articles in international journals, human resource development on thermodynamic assessment, and a more robust Calphad database for elevated temperature alloy design. |