Integrated Modelling and Calculation of Phase Diagram of the Pt-Al-Cr System

Author of the article:HUANG Yongxing 1 , WANG Puziyu 1 , CHONG Xiaoyu 1,2 , GAO Xingyu 3 , SONG Haifeng 3

Author's Workplace：1. Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China; 2. National and Local Joint Engineering Laboratory for Advanced Solidification Forming and Equipment for Metals, Kunming University of Science and Technology, Kunming 650093, China; 3. Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China

Key Words： superalloy; Pt-Al-Cr system; calculation of phase diagrams; thermodynamic model

Abstract： The construction of a pertinent thermodynamic database is a prerequisite to move forwards with the development
of Pt-based superalloys with outstanding mechanical characteristics and oxidation resistance. In this paper, thermodynamic
data of the Pt-Al-Cr system, experimental phase diagram data and data from first-principles calculations are systematically
compiled and evaluated. Thermodynamic properties, such as the enthalpies of mixing and formation of Pt-Al, Pt-Cr, and
Al-Cr, are calculated, and the calculated phase diagram and thermodynamic properties are in good agreement with
experimental data and data from first-principles calculations. Based on this, the composition-temperature phase diagram
model of the Pt-Al-Cr ternary system is built by the thermodynamic extrapolation optimization combined with the
CALPHAD (calculation of phase diagrams). This model is used to calculate the liquidus surface projection diagrams and
isothermal sections of the Pt-Al-Cr system at 873.15, 1 073.15 and 1 273.15 K. The thermodynamic calculation results are
in good agreement with the experimental data.