Where the Lines Cross

Alex O'Brien was a teenager in Springdale when the ground started shaking.

Fracking operations across the border in Oklahoma triggered earthquakes in a region that rarely felt them, he said. People insisted it had nothing to do with the drilling, but O'Brien wasn't convinced.

"I've lived here my entire life," he said. "And this is pretty new."

He didn't know what to do about it yet. But something shifted for him. There had to be a better way to power the world, and he suspected the answer would come from connecting things other people kept separate.

That instinct earned him a spot on the Forbes 30 Under 30 list for 2026 in Manufacturing and Industry for founding a company at the leading edge of nuclear fusion and 3D-printed metal.

But the story of how he got there starts in Arkansas.

A Band Nerd

O'Brien enrolled at the University of Arkansas and chose chemical engineering because the discipline sat at the crossroads of chemistry, materials and applied problem-solving. Then he added a second major in physics, drawn to understanding matter at its most fundamental level. One crossroads apparently wasn't enough.

He also played saxophone in the Razorback Marching Band for all four years, serving as section leader his senior year.

A self-described "band nerd," practice wasn't an escape from his academic life so much as a different kind of laboratory. Holding two demanding intellectual worlds simultaneously — materials and equations in the classroom, timing and ensemble precision on the field — trained him to think in connections rather than channels. When big decisions loomed, he found clarity making music.

"Deciding on what grad school I'm doing or what kind of research I want to do ... just taking a break from that, going to band and playing music for a while made it seem a lot simpler when I come back to it," he said.

An Honors College Fellow, he studied renewable energy abroad in Spain and attended a nuclear summer school. Heather Walker, teaching associate professor in chemical engineering at the university, watched him build that breadth in real time.

"As an undergraduate, Alex made the most of every opportunity, pursuing a double major, studying abroad, conducting honors research, serving in student leadership roles and attending Nuclear Summer School," Walker said. "His curiosity, initiative and willingness to pursue new opportunities position him to excel in advanced research environments and beyond."

By the time he graduated in the Class of 2019 from the Ralph E. Martin Department of Chemical Engineering, O'Brien had developed something harder to teach than any single discipline.

"I don't have to be in one narrow channel with everything I do," he said. He didn't leave knowing exactly where he was headed. He left the university, as he put it, knowing how to learn.

The Leap

The summer before his junior year, with no particular plan, O'Brien applied to a nuclear chemistry program in California. He got in, had nothing else lined up, and went. Nuclear energy clicked with him in a way nothing else had. It produces nearly 20% of the country's electricity, quietly and efficiently, and almost nobody talked about it unless something went wrong.

After that summer, graduate school felt inevitable. MIT did not. O'Brien had a chemical engineering degree, not a nuclear one, and he felt the gap.

"There was this fear in me that says, why would anybody accept me into a nuclear grad program? That's not what my degree is," he said. "Applying to MIT already felt like a big risk, so I said, might as well make it even bigger to do fusion research."

Fusion, the process of forcing atoms together rather than splitting them apart, is experimental technology that promises enormous power from small amounts of fuel. It produces far less radioactive waste than conventional nuclear fission. This promising technology has also been 15 years away for the last 50 years, O'Brien mused.

He saw an opening. The physics of fusion was getting enormous attention. The materials problem was not.

The Six-Month Problem

At MIT, O'Brien zeroed in on a question hiding in plain sight: what happens to the metals holding the reactor together?

The answer was not encouraging. He found research suggesting that if engineers built a fusion reactor with today's best alloys and switched it on, they might need to replace every metal component within six months. The heat, radiation and corrosive conditions inside a fusion device would degrade the structure faster than any existing power system.

"That is a huge problem," he said. "You can't make it economic if you're having to replace the entire reactor every six months."

His solution was, characteristically, a convergence. Metal matrix composites, materials that blend metals with small amounts of ceramic for added durability, had existed since the 1960s but were nearly impossible to manufacture uniformly. Metal 3D printing, meanwhile, had matured for entirely different reasons.

What O'Brien and his collaborators recognized was that these two separate fields solved each other's problems: the laser process used in 3D printing melts and resolidifies metal so quickly that it can lock ceramic particles in place, something traditional methods cannot do.

'It Feels Wrong to Just Leave It There'

By 2023, O'Brien had results he was proud of: printable nickel superalloys reinforced with ceramics that were stronger, more heat-resistant and far more durable under radiation than conventional metals. He expected the fusion industry to be ready.

It wasn't. Not yet.

"It started out being very disappointing," he said. "I spent my entire Ph.D. working on this technology. It feels wrong to just leave it there when we felt like it was a success."

The fusion companies told him the materials work was promising, but the plasma physics still needed solving. They would circle back. He had been early, not wrong, and for someone who had spent four years building toward this moment, the distinction didn't make it sting less. 

But his adviser, professor Ju Li, and his collaborator Kangpyo So saw what O'Brien was already beginning to see: the technology didn't just work for fusion. It worked for any industry that needed metals to survive extreme conditions.

"Alex has an unusual ability to move between deep technical research and real-world application," said So, who became co-founder and chief technology officer of the company they launched together.

"During his Ph.D., he pushed our materials work toward 3D printing and fusion, and, when he recognized the market opportunities, he showed the same determination in building AtoMe. That combination of scientific rigor and entrepreneurial drive is rare."

Printing Metal

AtoMe, pronounced "Atom-E," is what O'Brien's dissertation looked like once it left the lab and became a company. He now operates a multi-ton-per-year production facility, running pilot programs with the enhanced nickel superalloys he spent his Ph.D. developing. The materials are designed to drop into existing manufacturing processes, offering better metal without asking customers to rebuild how they work.

The use case he returns to most is turbines. When a critical part fails in a power-producing turbine, replacing it through traditional supply chains can take six to 12 months. AtoMe's goal is to make those parts 3D-printable in days.

When Forbes called with news of the 30 Under 30 recognition, O'Brien said he was "surprised as heck." But when he looked at the list and saw how many other honorees were working in materials, the surprise faded. "Clearly somebody got it," he said. "They understood that we need better materials."

Fifteen Minutes Away

O'Brien lives in New Jersey now, running his company and raising twin daughters. His saxophone sits in a closet. He says it stares at him, reminding him he needs to find some time to relax. He still misses Slim Chicken's and Flying Burrito back home.

But when he thinks about what would help more Arkansans pursue careers in STEM, his answer is simple: awareness.

"Even as a high schooler, growing up in Springdale, I was 15 minutes from the U of A," he said. "I knew very little about what kind of science was being done. There's groundbreaking work being done in Fayetteville, Arkansas, that people don't realize."

His advice to current students is to stop waiting for permission.

"Your degree is more about learning how to learn than it is putting you on a life track," he said. "If this is what you're passionate about, just go ahead and ask."

"Any success I have nowadays, any success I'm going to have in the future, I learned how to do it at the program there," he said. "I give all the thanks in the world to the U of A and to the engineering school and to the physics department."

The science that made AtoMe possible was developed at MIT. But the mind that saw where the lines cross, that was built in Arkansas.

About the College of Engineering:  The University of Arkansas College of Engineering is the state's largest engineering school, offering graduate and undergraduate degrees, online studies and interdisciplinary programs. It enrolls more than 4,700 students and employs more than 150 faculty and researchers along with nearly 200 staff members. Its research enterprise generated $47 million in new research awards in Fiscal Year 2025. The college's strategic plan, Vision 2035, seeks to build the premier STEM workforce in accordance with three key objectives: Initiating lifelong student success, generating transformational and relevant knowledge, and becoming the destination of choice among educators, students, staff, industry, alumni and the community. As part of this, the college is increasing graduates and research productivity to expand its footprint as an entrepreneurial engineering platform serving Arkansas and the world. The college embraces its pivotal role in driving economic growth, fueling innovation and educating the next generation of engineers, computer scientists and data scientists to address current and future societal challenges.