core sector communique

Finding the Softer Side of Steel

 

(Iranian-American scientist's metal foam offers greater safety in many uses) 

 

By Jeff Baron

Staff Writer

 

Washington - People have been working with metal for thousands of years to make it harder, tougher, stronger. Afsaneh Rabiei has made it fluffier.

 

Her invention promises to save energy and lives.

 

Rabiei is an associate professor of mechanical and aerospace engineering at North Carolina State University in Raleigh, and the metal foam for which she was awarded a patent in January is lightweight and strong but can absorb energy as it compresses. Picture a steel or aluminum bar, but with thousands of little air pockets, like a sponge. Hers isn't the first metal foam, Rabiei said, but it's by far the strongest because its air cells are uniform in size, uniformly round, with uniformly thick walls; the foam is made of tiny, hollow steel spheres embedded in a matrix of steel, aluminum or some other material.

 

Use it to make aircraft parts and they will be far lighter. Use it behind the bumper of a car and it will absorb much of the impact of a crash, keeping the body of the car - and the bodies inside it - far safer.

 

Depending on the materials used and the size of the hollow spheres - the ones Rabiei and her students have used range in diameter from 1.4 millimeters to 4 millimeters - the foam will withstand a certain amount of force before it begins to absorb the energy and compress.

 

"There's a lot of interest from a lot of different industries" to use her foam in a variety of applications, Rabiei said, and the university will negotiate licensing agreements for it. Rabiei said one of the truths of her field is that new materials will be put to uses their inventors would not have expected. But, she said, "what I had in mind was to make a material that is light and protects life."

 

Rabiei said she has been excited about metals since she was a schoolgirl in the Iranian city of Arak. "I remember we had a tour from a company in Arak when I was in high school, and I was really impressed by seeing these red-hot materials being formed," she said. So when she began her university career, at Sharif University of Technology in Tehran, she started studying materials science and engineering.

 

When Iran closed universities in 1980 during the Cultural Revolution in an effort to make sure that their teaching complied with the beliefs of the regime, Rabiei turned to her academic adviser for help on continuing her studies. He suggested that she translate some material on materials science from English into Persian, and she ended up translating a 600-page textbook on metallurgy.

 

"It was way above my head," she said. As a result, she learned her subject and learned an even more important lesson.

 

"I think that book opened my way, because I figured out that you can basically do what you want if you put your mind to it," Rabiei said.

 

She credited her parents for supporting her efforts - her mother, a poet, became her editor - and after classes resumed, she went looking for a publisher. "For me, the important thing was to get it published while I was a student," she said, and she succeeded. Her translation remains in print as a reference in the field, she said.

 

After graduation in 1986, Rabiei worked as a research engineer in Iran for a few years, but she said she wasn't content; she wanted to keep learning. "I told my mother, 'I think I still have to go find the ocean,'" she said.

 

She also made herself a promise: "When I turned 30, I decided I was going to get a Ph.D., I was going to be a professor in the United States, and I was going to have a child by the time I was 40."

 

For the Ph.D., Rabiei went to Japan. Colleagues from a Japanese company that partnered with her employer encouraged her, and she chose Tokyo University. After that, she spent three years on a research fellowship at Harvard University. At each school, she said, she found a valued adviser who helped her along.

 

"I was a hard-working person, and I was a very lucky person to end up working with such great people," she said.

 

At a party at Harvard celebrating Nowruz, the Iranian new year, she also met the man she would marry. She began teaching, and her daughter was born soon after. She had met her goals from 10 years earlier.

 

Rabiei said that her daughter recently came home from school and told her that girls may not be able to become scientists. That prompted a discussion about what women can do and a school report by the daughter about Rabiei's childhood role model, physicist Marie Curie.

 

Rabiei said she was aware from the start that she was going into a field in which women are rare. She was the first woman in her professor's lab at Tokyo University, and the first in her department at North Carolina State University. "I think we have a long way to go, wherever you go in the world, to build equity between women and men," she said.

(This is a product of the Bureau of International Information Programs, U.S. Department of State. )