PITTSBURGH (June 25, 2021)… CALPHAD (CALculation of PHAse Diagrams) is one of the genomic toolkits for material design and has recently been widely used in alloy innovations, ceramic design, process optimization and microstructure engineering. Its powerful, time-reducing skills are an incredible resource for thermodynamics research, especially for the development of novel functional alloys.

The use of CALPHAD to identify 21st century alloys is the focus of Wei Xiong of the University of Pittsburgh, who received the first CALPHAD Young Leader Award at the 50th Annual CALPHAD Global Conference (CALPHAD Global) this June.

“I am delighted to receive the first CALPHAD Young Leader Award and thank my colleagues and friends for their endless support and guidance,” said Xiong, assistant professor of mechanical engineering and materials science at the Swanson School of Engineering at the University of Pittsburgh. “I’m looking forward to organizing the Young Calphadian Workshop at the next CALPHAD annual meeting in Sweden.”

The CALPHAD Young Leader Award is given by the CALPHAD Advisory Board to a researcher under 40 years of age who has demonstrated high achievements and active participation in the CALPHAD community as well as strong leadership qualities. Self-nomination is not permitted.

In addition to the CALPHAD award, Xiong and PhD student Liangyan Hao received the Best Paper Award from the Alloy Phase Diagram International Commission (APDIC). The publication “An Evaluation of the Mn-Ga system: Phase diagram, crystal structure, magnetism, and thermodynamic properties” (DOI: 10.1016 / j.calphad.2019.101722) was selected from all journals as the best published manuscript on material thermodynamics in 2020 .

According to Xiong, the basic thermodynamics of the Ga-Mn (gallium-manganese) alloys are important for applications in magnets, spintronic devices, semiconductors, etc., but differences between the available Ga-Mn phase diagrams can hamper research. Through extensive and critical reviews, Xiong and Hao proposed a new phase diagram for the Ga-Mn system to aid future thermodynamic modeling and the design of novel functional alloys. Its publication was funded by the National Science Foundation as part of the project “Mechanisms of hierarchical microstructure formation under rapid solidification of Functional Heusler alloys” (NSF DMR 1808082).

Xin Wang, another PhD student from Xiong in his Physical Metallurgy and Material Design Laboratory, also received the Best Poster Award for his CALPHAD-based Integrated Computational Materials Technology (ICME) on the subject of “Uncertainty Quantification of Alloy Powder for Additive Manufacturing”. This research focused on solving a critical problem in powder manufacturing for additive manufacturing: the pre-alloyed powder composition often deviates from the target composition, which leads to undesirable properties and malformations.

In this work, Wang carried out a high throughput simulation to predict critical properties such as yield strength, impact transition temperature and printability. He then proposed an optimized alloy composition that shows an almost 100 percent chance of producing the successful additive manufacturing component. The strategy presented is general and can be applied to other alloy composition optimizations to expand alloy choices for additive manufacturing.

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Financial support for this research is used by the Office of Naval Research (ONR) program Additive Manufacturing Alloys for Naval Environments (AMANE) (Contract No .: N00014-17-1-2586 Integrated Computational Materials Design for Additive Manufacturing of High-Strength Steels ) granted in marine environments). This research project has published five high impact papers so far:

– Xin Wang, Wei Xiong, “Uncertainty Quantification and Composition Optimization for Alloy Additive Manufacturing Through A CALPHAD-based ICME Framework”, npj Computational Materials, Nature Publishing Group, 6 (2020) 188. https: //doi.Organization/10.1038 /s41524-020-00454-9

– [Editor’s Choice Article] Xin Wang, Soumya Sridar, Wei Xiong, “Thermodynamic Investigation of New High-Strength Low-Alloy Steels with Heusler Phase Reinforcement for Welding and Additive Manufacturing,” Journal of Phase Equilibria and Diffusion, 41 (2020) 804-818. https: //doi.Organization/10.1007 /s11669-020-00828-y

– Soumya Sridar, Yunhao Zhao, Wei Xiong, “Cyclic Re-Austenitization of Copper-Containing High-Strength Low-Alloy Steels, Manufactured by Laser-Powder Bed Fusion”, Material Characterization, 166 (2020) 110437. https: //doi.Organization/10.1016 /j.matchar.2020.110437

– Soumya Sridar, Yunhao Zhao, Kun Li, Xin Wang, Wei Xiong, “Post-Heat Treatment Design for High-Strength Low Alloy Steels Processed by Laser Powder Bed Fusion”, Materials Science and Engineering A, 788 (2020) 139531. https : //doi.Organization/10.1016 /j.msea.2020.139531

– Fuyao Yan, Wei Xiong, Eric J. Faierson, Gregory B. Olson, “Characterization of nano-scale oxides in austenitic stainless steel processed by powder bed fusion”, Scripta Materialia, 155 (2018) 104-108. https: //doi.Organization/10.1016 /j.scriptamat.2018.06.011

https: //News.Engineering.pitt.edu /pitt-faculty-students-capture-top-awards-at-2021-calphad-global-conference /

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