ICAMS / Interdisciplinary Centre for Advanced Materials Simulation


Third-generation thermodynamic database development using the ESPEI software: Application to the Fe-Cr and Fe-Ni systems

Date: 28.06.2018
Place: Sino-German Symposium: Modelling of thermodynamics, kinetics and microstructures in alloys, Bochum, Germany

Abdulmonem Obaied
Aleksei Egorov
Brandon Bocklund, Department of Materials Science and Engineering, Pennsylvania State University, University Park, USA
Irina Roslyakova, BASF SE, Ludwigshafen, Germany

The development of large multicomponent CALPHAD databases is limited by the time required to evaluate the constituent binary and ternary systems which grow with the square and cube of the number of elements in the database, respectively. Once developed, these databases are challenging to maintain because changing the model or parameters of a constituent unary of binary system requires updating all the higher order systems that depend on it, which limits the development and adoption of new models into existing thermodynamic descriptions. This issue has become especially relevant in connection with the development of third-generation CALPHAD databases, such as recently proposed Segmented Regression (SR) model [1]. The main goal of which is to create an accurate physically-based model for pure elements down to 0K. To address above mention challenges ESPEI software package was recently developed [2, 3]. It provides a tools for quick and automated reassessment within a CALPHAD method. The purpose of this study was to test the capabilities of the ESPEI by using it for reassessment of Fe-Cr binary system with standard SGTE and SR models for pure elements. As a first outcome, thermodynamic descriptions for fcc, bcc and liquid phases were obtained. Phases equilibria results and calculated mixing enthalpies show remarkable agreement with the previous studies and with experimental and DFT data. It was clearly shown that ESPEI enables automated model parameter generation and thermodynamic database development. References [1] I. Roslyakova, B. Sundman, H. Dettec, L. j. Zhang, I. Steinbach, Modeling of Gibbs energies of pure elements down to 0K using segmented regression, Calphad V. 32 1-8 (2016). Calphad v. 55 165-180 [2] Shang, S. L., Wang, Y., & Liu, Z. K. ESPEI: Extensible, self-optimizing phase equilibrium infrastructure for magnesium alloys. In Magnesium Technology (2010) pp. 617-622 [3] www.espei.org

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