Take Aim: The Five Hottest Problems in Materials Engineering

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Meet the Experts

Ruyan Guo

Ruyan Guo, PhD
Dr. Ruyan Guo is the Robert E. Clarke Endowed Professor of Electrical and Computer Engineering at the University of Texas at San Antonio, where she also serves as director of the interdisciplinary graduate program in advanced materials engineering.

Prior to joining the faculty of UTSA in 2007, Dr. Guo was a tenured professor of electrical engineering at the Pennsylvania State University, being the first woman at the rank of a tenured full professor in the department history.

Dr. Guo has been an active researcher and educator working in the frontier of materials science and device engineering. She conducts cutting-edge research in interdisciplinary areas of electronic and optoelectronic materials and devices, more recently on multiferroics, lead-free electronic ceramics, and piezoelectric resonance controlled phenomena, with immense potential in sensor, actuator, and biomedical applications. Over the years Dr. Guo, as a PI or a co-PI, has been awarded multiple research grants by the National Science Foundation, the Department of Defense, DARPA, and private industry.

Michael Tonks

Michael Tonks, PhD
Dr. Michael Tonks is professor and alumni professor of materials science and engineering at the University of Florida, where he is also associate department chair of materials science and engineering. He received his PhD from the University of Illinois, Urbana-Champaign.

Dr. Tonks is an active researcher in computational materials science at the microstructure scale. He runs the Tonks Research Group at the University of Florida, which investigates the degradation of the performance of materials operating in harsh environments such as in nuclear reactors, in space, inside of a gasoline engine, and inside of batteries, etc. His research has been funded by the Department of Energy, NASA, the Department of Defense, and private industry. He has published over 125 peer-reviewed papers summarizing his research. Notably, he won the Presidential Early Career Award in 2017 and the TMS Brimacombe Medal in 2022.

Reducing the Environmental Impact of Plastic

“Plastic is a great example of this amazing material that we didn't have until material scientists invented it,” Dr. Tonks says. “It’s super adaptable. You can use it for all kinds of things. But we almost engineered it too well.”

Cheap, strong, and versatile, plastic has found innumerable applications in the modern world. But one of its most superlative qualities—its durability—has had enormous negative environmental side effects. Entire islands of plastic float on the surface of the Pacific, and the plastic at its depths will outlive all the creatures that swim through it. According to the UN Environment Program, some 400 million tons of plastic are produced every year.

Materials engineers are approaching this problem in two distinct ways. The first is to find ways to break down the plastics we already have. The second is to find a way to engineer a new type of plastic that can retain its best traits but create a more neutral environmental impact. A breakthrough in either area would give the planet much more room to breathe.

Designing Better Semiconductors

“Given the increased global emphasis on environmental responsibility, and also frankly given the unsustainable increase in power consumption in computing and by data centers, the development of ultra energy efficient semiconductors, including on-chip memories, would be very important,” Dr. Guo says.

The focus here goes beyond conventional silicon technology, Dr. Guo notes. Wide bandgap materials like silicon carbide (SiC) and gallium nitride (GaN) allow for devices that operate at higher voltages, frequencies, and temperatures more efficiently than traditional silicon-based devices. That means less energy loss in power conversion and lower electricity consumption overall. Further advances in this area could make everything from the smallest consumer electronics to the largest electric vehicles less energy-hungry.

Dr. Guo also points to the integration of multiferroic materials in silicon and semiconductors. Multiferroic materials, which exhibit more than one ferroic property (such as ferromagnetism and ferroelectricity), can increase the functionality of semiconductors and make them smaller and less volatile. The resultant boost to energy efficiency would be useful in everything from extending the battery life of a portable device to meeting the power needs of a large data center.

Effectively Leveraging AI and ML

“A paradigm-shifting breakthrough in materials engineering would most likely involve the invention or discovery of materials with unprecedented properties or functionalities,” Dr. Guo says. “Some of the most impactful functionalities may be, for example, exceptional conductivity, revolutionary mechanical properties such as strength, or the ability to self-assemble, self-repair, or self-sustain.”

Artificial intelligence (AI) and machine learning (ML) have applications in practically every engineering discipline, and materials engineering is no exception. The computational power and pattern recognition capabilities of AI and ML algorithms show immense promise in identifying new materials with desirable properties. They’re also adept at crunching data sets unfathomable to the human mind.

“Unleashing the power of AI, combined with cloud or quantum computing, we could learn from the vast collection of experiments throughout human history,” Dr. Guo says. “We could decode the DNA of the molecules, the ionic clusters, and the assemblages of those smallest building blocks.”

Materials engineers are hopeful that AI and ML will be used to map incredibly small and detailed characteristics of materials, down to their crystalline structures and the grain boundaries that differentiate them. It could revolutionize our understanding of materials, as well as our design and fabrication of them.

But challenges remain. AI and ML are particularly good at interpolation, which fits new data onto an existing curve, but are less reliable when it comes to extrapolation, which goes beyond the data on record to draw new conclusions and inferences.

“We just don’t know what ML is going to be great for, and what it won’t be,” Dr. Tonks says. “Probably in five or ten years, we’ll have a better idea. But right now, we’re just trying it on everything and getting really good results in some cases and not-so-good results in others.”

Improving Energy Storage & Creation

More efficient batteries unlock a whole new world of possibilities. Consider the electric vehicle: more than developments in its chassis or motor, it was revolutions in lithium-ion batteries that made its concept feasible. The next generation of batteries will store energy more efficiently, have a longer lifespan, and enable more renewable energy.

“We need more renewable, carbon-free energy,” Dr. Tonks says. “But a really big challenge is that we can’t always get the energy when we need it or where we need it. We need better ways of storing it.”

Materials engineers have already had a significant impact on renewable energy creation. Advances in solar cell technology are largely attributable to materials science, which has helped turn what was once a niche energy source into one of the planet's most reliable forms of renewable energy. That success has many engineers reconsidering another carbon-free source: nuclear power.

“When we think of nuclear power, we often think of the old reactors that we’ve had for a long time, and they have some issues,” Dr. Tonks says. “One issue is that they’re big and expensive to make. Another issue is they’re not very good at using up all of the energetic material within the fuel. But now it’s an exciting time: there are new, smaller reactors, and also reactor types that are more fuel efficient. So suddenly there’s a big renewed interest in nuclear power.”

Adapting Materials to Harsh Environments

Most of the issues that nuclear reactors face are related to the fact that the conditions within that reactor are harsh. That plays into a wider theme of materials engineering, which is that harsh environments—whether in temperature, pressure, or some combination of factors—can corrode, warp, or break down materials in undesired or unpredictable ways. Meanwhile, the terrain of the future is a map of harsh environments: high orbit, atmospheric re-entry, the ocean depths, interplanetary travel, and outer space.

“Innovations in materials that can withstand extreme conditions such as high temperature and high power are critical for advancement in electric vehicles, for exploration of space and aerospace, and for energy industries,” Dr. Guo says.

Adapting materials to harsh environments could even unlock the holy grail of so many engineers: fusion power. Fusion power is what powers our Sun, where extreme pressure and temperature fuses hydrogen atoms together to produce helium atoms, generating abundant light and heat. Such conditions are—so far—impossible to recreate safely on Earth.

“There’s not a single material that can fit the needs of a fusion reactor,” Dr. Tonks says.

“So at the same time as we’re working to try and get a stable fusion reaction, we’re also working hard to come up with some new ideas for the materials within the reactor itself.”

Outside-the-box ideas such as lithium fountains have been suggested as possible material solutions to the problem of housing a stable fusion reaction. But outside-the-box thinking is the wheelhouse of materials engineers, who are tasked with envisioning and building what does not yet exist. In materials engineering, non-existence isn’t the sticking point—it’s the starting point.

“There’s a problem that’s always going to be happening at the frontier of development, where someone comes up with some crazy new idea, and there’s no material available that can do what they need to build it,” Dr. Tonks says. “That’s when they have to come to material scientists.”

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