“Metal production is like cooking,” says C. Cem Tasan. “Sometimes you try to optimize a recipe and find new ingredients to bring in, and sometimes you have a crazy idea — like adding orange to chicken — that turns out wonderfully.”
Tasan, who started in January as the Thomas B. King Career Development Professor of Metallurgy in the Department of Materials Science and Engineering, has come to MIT in the hope of refining and creating recipes for metallic materials. His research, which involves investigating and tailoring the structure and behavior of metals from the nano- to the macroscale, touches a wide range of industrial applications, including automotive production, building construction, and energy production. “There are so many degrees of freedom working in metal design,” he says. “It is an infinite space, where you can try weird things, and create new properties. There is traditionally lots of trial-and-error, whereas my research is guided by ‘imaging’ the relevant microstructural processes as they take place.”
A native of Turkey, Tasan became transfixed by the possibilities of metallurgical research while pursuing his master’s degree at the Middle East Technical University in Ankara. He was a teaching assistant in a microscopy course, browsing through the “beautiful microstructure variations” possible in steels, when he saw “the limitless options in designing new microstructures and unprecedented properties” in metals. It was, says Tasan, a “career-defining” experience. He went on to earn a PhD at the Eindhoven University of Technology in the Netherlands, and then became a postdoc and research group leader at the Max-Planck Institute for Iron Research in Düsseldorf.
Specialized tools are essential in accomplishing Tasan’s research, which involves interrogating and manipulating the microstructure of metallic materials in situ. “For example, if you look at a metal microstructure, there are typically softer and harder zones, and they can deform in different ways locally,” he says. “Just like when you’re making a cake, and you pull the dough with nuts in it in two directions: the dough expands but not the nut. If one can successfully image such processes, which take place at micro- or nanoscales in metals, one gets tremendous insight on how to design superior materials.”
Now at MIT, Tasan’s test kitchen is a laboratory outfitted with high-powered microscopes and technologies of his own devising, which he uses both to detail the physics of how metals fail, and to design formulas for improving their resiliency. In 2018, after the completion of MIT.nano, the new materials research facility going up in the center of campus, Tasan says he will be even better equipped, with the help of “dedicated high-end tools that will push our understanding of microstructure physics even further.”
Tasan believes that his research can help encourage transformations in industries that produce and consume metals — which also happen to be top consumers of energy and producers of CO2 emissions. What if, he asks, metal recycling is not the best way to address climate change?
“Recycling used metals back to the beginning of their processing cycle is not always the most eco-friendly solution. We need clever materials solutions to cut down emissions,” Tasan says. “My alternative is making metallic components that, with a feasible treatment, can return to their preservice state — while they are still in service.” He has designed a novel process that uses brief exposure to high temperatures to rearrange the atomic microstructure of a piece of metal that has been deformed, to transform it back to its original condition. “There are several examples, but my favorite is a nanostructured steel where we can heat-treat deformed samples very briefly, then zip, it’s done,” he says.
Tasan has projects on “healability” of automotive components, but discussions with partners reveal that the strategy could be applied in various industries looking to employ lighter-weight, more energy efficient components. In fact, some basic healing methods have been considered or are already in use for some applications: e.g. in urban infrastructure, such as bridges, that face a pounding and require regular replacement due to wear and tear. “Especially for applications where access is an issue, for example in a power plant, or spacecraft, it would be extremely useful to have healable components” he adds
For Tasan, finding ways to defeat failure in metal and concocting metals that are strong, tough, light, and healable may be just the start. As he extends his “cooking and design skills,” he says, “my goal is to design materials we can use forever.”