Composing the Future with a Symphony of Materials
Interview with Ken Reifsnider, Director, HeteroFoaM Center
In college, students are oft-advised to be well-rounded so as to become interesting and multi-talented individuals, but few people embody that idea as much as Ken Reifsnider, Director of the Heterogeneous Functional Materials (HeteroFoaM) Center. Talented in both music and mathematics, he turned down an opportunity to enroll at the highly selective Eastman School of Music to obtain degrees in mathematics and mechanics on scholarship at the Johns Hopkins University.
Reifsnider held an early fascination with nature's ability to make a variety of tiny, complex structures using only a few elements. For example, in DNA only 5 different elements come together to form a double-helix structure that is 2 billionths of a meter wide (one 25,000th of a human hair) and is responsible for all forms of life. Ultimately, it was the way mathematical models could be applied to understand the properties of engineering materials that drew him to materials science. He continued his study at Johns Hopkins with a Ph.D. in Materials and Metallurgy while, ever the active individual, he took up wrestling and intramural lacrosse, no less at a school historically adorned with national lacrosse championships.
Music was not lost on him, though. Reifsnider continued cultivating his musical pedigree by forming a dance band, singing in college choruses, performing with a glee club, and playing trumpet for bands in the Baltimore Musician's union.
Following his Ph.D., Reifsnider spurned more lucrative opportunities to work at Virginia Tech so that he could be involved with students in both teaching and research. He formed the "Materials Response Group" at Virginia Tech and eventually became the chair of the Materials Science and Engineering Ph.D. program for 19 years, and received the Reynolds Metals professorship in 1989.
With the help of colleagues and students, Reifsnider co-founded the Center for Composite Materials at Virginia Tech, where he also developed courses and concepts that became part of the foundation for the design of composite materials. Composite materials are combinations of materials that use the best aspects of each individual material. For example, carbon-fiber-reinforced plastic takes advantage of the high stiffness and strength of carbon fibers and the light weight of plastic. As a result, composite materials can be tailored to replace traditional engineering materials, like aircraft aluminum. Reifsnider’s efforts led to the commercialization of composite technology, which enabled advances like the composite airframe in the new Boeing 787.
Reifsnider's work culminated in the 2002 in a landmark textbook, Damage Tolerance and Durability of Material Systems, which codified the ideas that he and his colleagues had developed to help solidify composite materials as a sustainable research field. Their approach was to rationally design composite materials by tuning the amount or types of fibers to achieve a prescribed "material state," defined by criteria like strength and stiffness, by tuning the amount or types of fibers. Reifsnider's work earned him election to the National Academy of Engineering in 2004.
Laying the foundation for composite aircraft structures was certainly an accomplishment, but, Reifsnider knew the story of heterogeneous material systems did not end with composite materials and their strength or their stiffness. If mechanical behavior could be designed by material systems, then why not thermal behavior, electrical behavior, or even chemical behavior? These areas are collectively known as multiphysics behavior, and they represented a metaphorical iceberg of knowledge waiting to be discovered.
When the Department of Energy's Office of Basic Energy Sciences announced the Energy Frontier Research Program in 2009, Reifsnider saw an opportunity to combine a quest to understand multiphysics behavior and answer clean energy challenges. He met with his colleagues from across the country and, in a stark airport conference room, drew up the blueprints to write the rest of the heterogeneous materials systems multiphysics story and answer the Department's grand challenges for clean, renewable energy. The project naturally attracted experts across the multiphysics spectrum from seven universities and three national laboratories.
As ambitious as the plan was scientifically, Reifsnider never lost sight of the people. Just as the proposed center would advance scientific knowledge about heterogeneous material systems in a holistic fashion, it would also advance the career development of scientists from the high school level to graduate school and beyond. Through support from the HeteroFoaM Center, graduate students and postdoctoral associates network and collaborate across the country, with a unique opportunity to lead their peers in teleconferenced research seminars. Just as the answers to the energy challenge will be long-term solutions, the Center has helped ensure that the scientific field itself has long-term prospects by enriching more than 1,500 teachers with workshops and training to better inspire and cultivate young minds. As director, Reifsnider fostered the spirit behind all of these efforts but allowed each to flourish in its own manner.
For budding scientists and students, Reifsnider advises building a strong foundation of fundamental knowledge and understanding of science. "Get as much skill as possible in mathematics and physics, because our world is increasingly diverse. We don't have strong labels and narrow specializations anymore − professions where you could work 10 or 20 years."
He added, "The physical world is a complex world we still don't understand, and the biosciences are full of incredible opportunities and material systems to study for inspiration."
Today, the HeteroFoaM Center enjoys fruitful progress in its research thrusts, garnering significant attention from the scientific community, with invited lectures in 14 countries, over 100 archival publications, and six patent disclosures filed, all in the past 3 years. The design of heterogeneous material systems for energy purposes led to improvements in properties like conductivity and energy storage by as many as 12 orders of magnitude.
Reifsnider recalled a childhood memory that became an analogy for the Center's approach to science. "I grew up with stationary engines. We ran them outside the barn, but they didn't go anywhere or do anything except provide power. Of course, we eventually put them on bicycles and cars and went uphill with them." He sees a future where material systems will make that same transition from exploiting their natural phenomenon to being able to design them purposefully.
"Our work is not just a new innovation; it's a new approach to science where we find ways to interact with our resources thoughtfully to make our society work. We need to do science for adaption, not adoption. Those stationary engines were adoption."
Reifsnider believes that the collaboration of a diverse set of experts in the HeteroFoaM Center will continue to foster successes. In the meantime, he stays active with a regular jogging routine and his lifelong dedication to music by practicing weekly at the piano.
About the author(s):
Samson Lai. A Ph.D. student at Georgia Tech and member of the HeteroFoaM Center, Samson is working on synchrotron-based in situ x-ray characterization of solid oxide fuel cells. Specifically, he is studying how catalyst infiltration improves cathode performance and how barium-based catalysts improve carbon and sulfur tolerance in anodes.