UCSD Scientists Set Sights on a Stronger, Tougher Material for Space : Research: An Army grant sends the panel on a search for the stuff of which a space station can be built to protect it from meteors.
Imagine a space station built of material so strong that the inhabitants would have no fear of being struck by a meteor.
That material doesn’t exist yet, but, with a 5-year, $2-million Army grant, scientists at UC San Diego have launched a search for new materials that would be stronger, tougher and more heat resistant than ones now available, university officials announced Monday.
“Without advances in materials, all innovation ceases--all technological developments grind to a halt,” said Sia Nemat-Nasser, a member of the four-person team of UCSD scientists from the Department of Applied Mechanics and Engineering Sciences.
“Materials make all technological development possible--from ceramic tiles that form the protective shield of space shuttles to the high-temperature superconductors that may revolutionize energy and transportation systems,” Nemat-Nasser said.
First, the scientists will analyze existing materials, focusing on steel, copper and titanium, to determine their atomic structures and how those affect the materials’ properties.
The group is not solely interested in the material’s strength. It also is seeking other properties, such as ductility, the ability of the material to bend without fracturing.
When debris was recently reported in the path of the space shuttle, NASA officials ordered a change of course. That is because today’s materials are neither strong nor ductile enough to withstand the impact of collision.
“It’s not just strength (that we are interested in)--it’s a combination of strength and ductility,” said Kenneth Vecchio, professor of materials science and a member of the research team.
Scientists today are thwarted by the shortcomings of existing materials. Steel, for instance, is ductile--or tough--but not very strong, Vecchio said. Ceramic materials, such as silicon nitride, are just the reverse--strong but not very tough.
If scientists could understand what part of a material’s atomic structures contribute to which properties, they could design a material selecting one desirable quality and dropping faulty ones, Vecchio said.
To achieve NASA’s goals of a launched space station, scientists will have to come up with new materials within the next decade.
But clearly, such materials would be useful on Earth as well as in space. A car’s engine block, for instance, could be constructed using something like silicon nitride, which is strong and can withstand high temperatures. This would allow an engine to run hot without needing a radiator or cooling system. Eliminating the cooling system would significantly reduce a car’s weight, enabling the engine to run more efficiently and use less gas, Vecchio said.
The grant, awarded by the Army Research Office, will allow researchers to develop sophisticated equipment and tools to test the properties of ductile and brittle materials. The work will combine techniques of mechanics and physics with high-performance computers.
In the beginning, researchers will work backward, taking a material and determining its atomic structure and how that structure affects its properties. The process is like assembling a jigsaw puzzle, Vecchio said.
“Understanding the atomic structure is like looking at pieces of the puzzle,” he said. “If you don’t know how each piece fits together, you cannot make the entire puzzle so you cannot see the big picture.”
Marc Meyers, professor of materials science, and Robert J. Asaro, professor of materials science and applied mechanics, also will work on the research team.
