Gallery 2
Paul E. Danielson

"I have been driven with a passion and fire in metallography for 46 years," says PAUL E. DANIELSON of the Department of Energy's Albany Research Center in Oregon, where much of his work has focused on characterizing metals used in power generation plants. Some of his most striking micrographs come from analyses of titanium, but he has worked with an enormous diversity of metals and alloys. "It often is beautiful art," Danielson says, "but it also helps my customers better understand what's going on with their materials."

Image 1, used also on the cover of the May 15 issue of Chemical & Engineering News, depicts flaws in a weld joining two titanium sheets. The dark blotches are voids where gas bubbles formed, and the blue region is associated with unwanted and bond-weakening reactions with oxygen and nitrogen. The following five images are also from titanium specimens. Image 2 shows both the long and smaller equiaxed grains that emerged when a piece of titanium sheet was cold-worked, probably through rollers, to strengthen it. Image 3, of cast titanium, relies on an optical technique to show impurities lining up in bands in the metal's grains. A different optical technique highlights the grains and phases of another piece of cast titanium in Image 4. Image 5 shows what happens internally when a cast-titanium ingot is forged into other shapes. Image 6, the last titanium image, is from a 22-mm-thick plate with grains made colorful with the use of polarizing filters. Images 7–9 show the internal structure and beauty of, respectively, cast vanadium, cast zirconium, and stainless steel.


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All images courtesy of Paul E. Danielson