Metallic memory?

Memory has traditionally been considered a function unique to living things, especially higher organisms. However, in their research, materials scientists have discovered that certain metals also have memory functions.

In the 1960s, researchers at the U.S. Naval Ordnance Laboratory made a nickel-titanium alloy wire from 55% nickel and 45% titanium. They wound this nickel-titanium alloy wire into a spiral coil, heated it to 150°C, then cooled and straightened it. When the alloy wire was heated to 95 ℃ again, there was an incredible scene - the wire automatically curled into the shape of the original spiral coil. Researchers once again to cool it, straighten, who knows when heated to the same temperature, it returned to the original shape. The experiment was repeated, and it worked.

Afterwards, scientists found that some other alloys, such as copper-zinc-aluminum alloys, copper-nickel-aluminum alloys, iron-platinum alloys, and so on, also have the function of this kind of memory shape, and they called this kind of alloys as "shape memory alloys".

This shape memory function of the alloy can be widely used in satellite antennas, aircraft hydraulic systems, pipeline riveting, medical equipment and many other fields. For example, the antenna made of them, usually folded up very small, when the spacecraft on the sky, in the sunlight irradiation, the antenna will unfold into a hemisphere with a diameter of several meters; artificial bone rod made of them, you can rely on the human body temperature will be fixed broken bones, greatly accelerating the speed of fracture healing.