Strength by laser

Researchers at Lawrence Livermore National Laboratory, along with colleagues at New Jersey-based Metal Improvement Co. Inc., use their Lasershot Peening System to extend the lifetime of critical metal parts, from aircraft engine fan blades (shown) to hip joints. Short-lived, repetitive blasts of light from a reliable, high-powered laser create an intense shock wave that peens the metal, putting compressive stress much deeper into the metal, significantly increasing resistance to cracking or corrosion. The system fires a 20-nanosecond laser pulse that is focused to an energy density of about 200 joules per square centimeter at the surface of a metal coated with dark paint and a thin overlay of transparent material, like water. The laser light passes through the water and is absorbed by the dark paint. Read more at www.llnl.gov/str/Hackel.html.