As one of the leading experts in his field, University of Virginia alumnus Michael Gao has spent the past 15 months convened by The Minerals, Metals & Materials Society to help identify the potential uses for high-entropy alloys. Formed by mixing five or more principal elements, these alloys exhibit exceptional combinations of strength, ductility and damage tolerance.
“Our main goal is to identify applications for high-entropy alloys that are important for defense and other industries,” said Gao, a physical scientist with the National Energy Technology Laboratory’s Materials Engineering and Manufacturing Directorate. “Then we identify the major challenges and roadblocks toward application and present a plan to solve those problems, working from the laboratory to industrial components and advanced manufacturing.”
The plan — “Defining Pathways for Realizing the Revolutionary Potential of High Entropy Alloys” — was released at the Second World Congress on High Entropy Alloys held December 5-8, 2021. Funding from the Defense Advanced Research Projects Agency, implemented through the Air Force Research Laboratory, supported the study.
Gao, who earned his Ph.D. in materials science from UVA’s School of Engineering and Applied Science in 2002, is among the 15 leading experts invited to join the accelerator study group. John R. Scully, the Charles Henderson Chaired Professor of Materials Science and Engineering at UVA, is also a member of the group.
“I love materials and materials science and am very dedicated to computational materials design,” said Gao, who fulfilled postdoctoral appointments at UVA and Carnegie Mellon University and joined the National Energy Technology Laboratory as a contract researcher in 2008. “I want to accelerate the design of cost-effective high-temperature materials that will improve the efficiency of gas-fired power plants, to reduce global warming and other environmental side effects.”
Gao, who resides in Oregon, felt these effects directly in 2020 when he was forced to evacuate his family from encroaching wildfires; last year was one of the most destructive fire seasons in the state’s history.
“We as a people must do better to save our environment,” Gao said. “Materials really play a big role, to improve efficiency. We need people dedicated to it, and we need better tools to help us do it.”
Gao specializes in computational thermodynamics, which he first learned from his UVA dissertation advisor Gary Shiflet, a professor emeritus of materials science and engineering. Materials scientists and engineers use a variety of computational tools that bridge the length and time scales to quickly identify the optimal combination of elements with the properties needed for extremely high-temperature environments.
“I felt early on that you need to have some type of computational skills under your belt,” Shiflet said. “In addition to being a good experimentalist, Michael’s work personifies how materials science brings chemistry, physics and computers together to unravel complexity. High-entropy alloys is just one area; once we push the boundaries, other material property areas are open to exploration.”
Gao is known for his embrace of continual, lifelong learning, and it was this thirst to fully understand material behavior that led him to UVA.
“I started my career as a mechanical design engineer for the China Petrochemical Corporation, following a standards-driven, cut-and-paste approach that set the special grades of chrome-molybdenum and stainless steels, the heat treatments to achieve desired microstructure and mechanical properties, and similar process requirements,” Gao said. “I wanted to know the physics behind it.”
He went to Sweden in 1996 to learn materials science in graduate school but found that the master’s degree was not enough.
“The Ph.D. is more of a journey, sticking with a professor-advisor,” Gao said. “Gary was always on the lookout for opportunities that would serve us best in the future. He understood the importance of design tools like CALPHAD [Computer Coupling of Phase Diagrams and Thermochemistry] that were just becoming available. He bought us a license and sent us to a summer course to learn it. But it was not plug-and-play; you really had to understand the fundamentals.”
These days, Gao combines artificial intelligence and machine learning with experiments and computational modeling — not just to run computer programs, but to understand the underlying mathematics and physics. Shiflet also appreciates the importance of AI and machine learning and funded faculty in these areas during his three-year tenure as a program director at the National Science Foundation.
“To remain competitive and protect our planet, we need new materials that are stronger, lighter and more corrosion resistant, and made available at lower cost,” Shiflet said. “I really believe, and have believed for a long time, that once we open up the area of complexity in alloys, aided by AI and machine learning, there’s a wealth of new materials that will help civilization.”