Webinar

Incorporating Insights from First-principles into Calphad Descriptions of Atomic Ordering

Historically, CALPHAD assessments considered many types of experimental data from various types of experiments to create an optimised thermodynamic description. As theoretical calculations become more readily available, new types of relevant data are accessible which give us new insights into materials that can be challenging or impossible to obtain experimentally.

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Using first-principles calculations, we can obtain information about defect formation energies, never seen but related metastable phases, and stable phases that are kinetically prevented from forming. These insights on an electronic and atomic level can be used to explain the origins of short- and long-range atomic ordering and can provide a holistic understanding of order-disorder processes that is difficult to obtain experimentally. In some cases, this new data can be incorporated into the assessment directly as part of the conventional optimisation process, but in other cases new models must be developed to accurately describe the underlying physics. Using the ultra-high temperature ceramic zirconium carbide as an example, this talk shows how first-principles calculations can unveil the mechanisms of ordering throughout its wide non-stoichiometry from 0 K up to the maximum melting point of 3700 K, incorporating these insights into a CALPHAD description.

This webinar is part of our Expert User Series, which invites experts from industry and academia to present their work with Thermo-Calc products.

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About the Speaker

Dr. Theresa Davey is an assistant professor in the Fracture and Reliability Research Institute within the School of Engineering at Tohoku University, Japan. She previously obtained her PhD and worked as a postdoctoral research associate in the Department of Materials at Imperial College London, UK. Her research focus is using physical insights from theoretical calculations and simulations to assist materials design, using multi-scale techniques from atomistic density functional theory (DFT) to the macro-scale CALPHAD approach. In particular, she is interested in improving the thermodynamic descriptions of point defects and short- and long-range ordering in alloys and ceramic materials. She has a strong interest in computational materials design and materials informatics, and has recently been exploring topics relating to uncertainty quantification and sequential learning of phase diagrams.