Stronger materials can make computers faster, jet engines more lightweight and protect Navy sailors under attack. After Northwestern’s McCormick School of Engineering bought a microscope valued at more than $2 million in December, it is one step closer to finding ways to make materials — such as steel and aluminum alloys — to meet these demands.
The Local-Electrode Atom-Probe microscope is the latest version of the 3-D atom-probe, and NU grabbed the fourth one in the world in December 2004. With the microscope, researchers can now look at particles on an atomic level to determine what makes the materials so strong, said Prof. David Seidman, who led the funding efforts to buy the microscope.
“(The microscope) lets us look at precipitates (within materials) at a sub-nanometer scale to determine their chemical composition,” said Seidman, a professor of materials science and engineering. “It helps us understand why nano-scale particles strengthen materials.”
Prof. Seidman heads NU’s Center for Atom-Probe Tomography, which is the second largest atom-probe tomography group in the world, according to a McCormick press release. Tomography is the use of X-rays to see details of one plane of an object and not others. The center and other groups on campus can use the microscope for their research, and there are about such nine research projects currently in progress, Seidman said.
Federal funding covered the majority of the microscope’s costs, he said.
The U.S. Office of Naval Research helped fund NU’s microscope because it wants blast-resistant material that will prevent another disaster like the USS Cole, Seidman said. The USS Cole was docked at a Yemen port in 2000 when an explosive-laden boat manned by terrorists drove into the ship’s side, killing 17 sailors and wounding 39 others.
The National Science Foundation also contributed to the funding in hopes of stronger, aluminum-based alloys — mixtures of elements — to can make jet engines lighter.
Pure aluminum, without other particles, would be too soft to even make a can, said Dieter Isheim, a professor of materials science and engineering.
“Adding alloying elements (that strengthen the material) typically make up less than 1 percent (of the material),” Isheim said. “They can make materials smaller or thinner which can save weight in a rocket.”
Research results will be reported in national science journals for public use. Private companies, such as Evanston-based QuesTek, which designs energy-efficient materials, can then use the results in real-world applications.
“(The Local-Electrode Atom-Probe microscope) is the only microscope that allows that kind of research,” said David Dunand, a professor of materials science and engineering.
Dunand will use the microscope to find aluminum alloys for more energy-efficient cars and to find superconductors that would improve CT scans and magnetic resonance imaging, also known as MRI.
“We wouldn’t be able to do it otherwise,” he said.
The microscope collects data 1,000 times faster and examines samples at a larger scale than older versions do. It could help solve the problems encountered with the old microscope, Isheim said.
On Tuesday, NU’s old 3-D atom-probe had collected 9 million atoms for an experiment started on Feb. 14, and the new microscope had collected 16 million atoms in an hour.
Reach Helena Oh at [email protected].
