Amy J. Clarke: Then and Now / 2012 Early Career Award Winner


There is an opportunity to improve how we manufacture parts by studying how metals behave under different conditions. Specifically, it’s important to study the first and crucial step in manufacturing, solidification. Casting, welding, and joining all depend on this process. 

The manufacturing process used affects the quality, properties, and performance of a part. So, it is important to comprehend the relationship between processing and the development of key microscopic features. Advanced observation methods are available at national user facilities and laboratories. The tools allow us to see how metals solidify in real-time at different length and time scales. These methods allow us to understand and control the freezing of metals from the liquid to solid state for advanced manufacturing.

Thanks to the Early Career Research grant from the Office of Science, we used state-of-the-art imaging techniques at the Advanced Photon Source user facility and the Department of Energy’s Los Alamos National Laboratory. 

We were able to observe metals (1) during directional solidification, where the solid-liquid interface advances under controlled heat environment to grow the solid, and (2) during traditional manufacturing processes like casting, where molten metal is poured into a mold and then solidifies to form a part. 

This allowed us to understand how microscopic structures form, and how manufacturing plants can modify processing conditions to affect solidification and defect development. This fundamental knowledge allowed us to incorporate changes in real-time. These real-time changes to the processing conditions allowed us to modify how the solidification structures developed and directly compare them to computer-based models.

This work has trained postdoctoral researchers and involved collaborations with experts at national laboratories and Northeastern University. The knowledge gained from this work enables the prediction and control of metal solidification dynamics, allowing for advanced manufacturing. 

The knowledge gained is also the foundation for our current research. 

We are using real-time visualization of microscopic structures and defects produced in metals under conditions far from equilibrium. In particular, we are studying rapid solidification conditions relevant to additive manufacturing, also known as 3D printing of metals.


Amy J. Clarke is the John Henry Moore Distinguished Professor in Metallurgical and Materials Engineering in the George S. Ansell Department of Metallurgical and Materials Engineering at the Colorado School of Mines and Co-Director of the Center for Advanced Non-Ferrous Structural Alloys.


The Early Career Research Program provides financial support that is foundational to early career investigators, enabling them to define and direct independent research in areas important to DOE missions. The development of outstanding scientists and research leaders is of paramount importance to the Department of Energy Office of Science. By investing in the next generation of researchers, the Office of Science champions lifelong careers in discovery science. 

For more information, please go to the Early Career Research Program.


Title In‐situ Monitoring of Dynamic Phenomena During Solidification


This project focuses on the ability to visualize experimentally and model theoretically the melting and solidification processes of metal alloy materials, even while at elevated temperatures. This project will use novel tools and unique probes, such as synchrotron x‐ray and proton radiography and tomography, at National Laboratory Facilities that have not yet been used in the United States for this purpose. Modeling these processes will enable the prediction of the microscopic structure of metal alloys, even under harsh environments, and will allow for new understanding of a range of energy materials, such as wind turbine blades and lithium rechargeable batteries.


AJ Clarke, D Tourret, Y Song, SD Imhoff, PJ Gibbs, JW Gibbs, K Fezzaa, A Karma, “Microstructure selection in thin-sample directional solidification of an Al-Cu alloy: in-situ imaging and phase-field simulations”, Acta Materialia, 129, 203 (2017). [DOI: 10.1016/j.actamat.2017.02.047]

AJ Clarke, D Tourret, SD Imhoff, PJ Gibbs, K Fezzaa, JC Cooley, WK Lee, A Deriy, BM Patterson, PA Papin, KD Clarke, RD Field, JL Smith, “X-ray imaging and controlled solidification of Al-Cu alloys toward microstructures by design.” Advanced Engineering Materials, 2015, 17, 454, (2015). [DOI: 10.1002/adem.201400469]

A Clarke, S Imhoff, P Gibbs, J Cooley, C Morris, F Merrill, B Hollander, F Marian, T Ott, M Barker, T Tucker, WK Lee, K Fezzaa, A Deriy, B Patterson, K Clarke, J Montalvo, R Field, D Thoma, J Smith, D Teter, “Proton radiography peers into metal solidification.” Scientific Reports,  3, 2020, (2013). [DOI: 10.1038/srep02020]  


Additional profiles of the Early Career Research Program award recipients can be found at the Early Career Program highlights page.

The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit the Office of Science website.

Sandra Allen McLean
Sandra Allen McLean ( is a communications specialist in the Office of Science’s Office of Communications and Public Affairs.
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