EVANSTON, Ill. — Materials scientists and engineers at Northwestern University are developing a new ‘high-security’ steel that would be resistant to bomb blasts such as the one that struck — and nearly sank — the USS Cole in Yemen in 2000. The researchers now have a state-of-the-art instrument that enables them to get a precise look at steel’s composition on the nanoscale: a $2 million atom-probe tomograph that is only the fourth of its kind in the world.
Using the new Local-Electrode Atom-Probe (LEAPÂ®) tomograph, researchers studying steel and other materials can — at amazing speed — pluck atoms off a material’s surface one at a time, layer by layer over tens of thousands of layers, to better understand the entire nanostructure and chemical composition of the material, which is key to designing new materials effectively and efficiently.
The technology is similar to that used in CT (computed tomography) scans, which image body tissues for medical diagnosis. Consisting of a field-ion microscope plus a special time-of-flight mass spectrometer, an atom-probe tomograph takes multiple pictures and uses those slices to construct a detailed three-dimensional image of the material.