Better Days

In 1959 chemist William J. Buehler of the Naval Ordnance Laboratory was trying to devise a missile nose cone that could withstand extraordinary heat and fatigue. He found a promising alloy of nickel and titanium and passed around a sample at a 1961 laboratory management meeting. The sample had been folded like an accordion, but in examining it Buehler’s colleagues flexed and twisted it out of shape. When of them idly held it over his pipe lighter, they got a surprise: The sample sorted itself back into its accordion shape.

Buehler’s alloy is now known as nitinol (for “nickel titanium Naval Ordnance Laboratory”), and this property is known as “shape memory.” In Nature’s Building Blocks, John Emsley notes, “Spectacle frames made from nitinol can be bent and twisted into remarkable shapes and, when released, will jump back to their original shape.”