Metals do not usually return to their original shapes after they have been bent because of their rigid structure. But, what if I tell you there IS a metal called shape-memory alloy that can do this! Cool right?
I wish I find that metal.
Once this shape-memory metal has been shaped, it always remembers that shape. Even if it is bent, shape-memory alloy returns to it’s original form when it is heated. This makes it useful in many places. Eg:- They are used for braces and dental arch wires, memory alloys maintain their shape since they are at a constant temperature, and because of the super elasticity of the memory metal, the wires retain their original shape after stress has been applied and removed.
HOW DOES IT RETURN TO IT’S ORIGINAL SHAPE?!
1] The metal is made in such a way that it will remember it is, for eg:- a blooming flower. The metal is made up of tiny particles that hold hands. The particles are lined up in a pattern that the metal remembers.
2] If you ever find such a metal, try closing the flower by hand. Even though this will change the way the particles hold hands, they do not let go off each other.
3]Now, the flower is placed in hot water. The heat allows the particles to change the way they hold hands, and they start to return to their original pattern.
4]Finally the particles line up in the pattern they were put into when the flower was first made, and the flower blooms again!
HOW DOES THIS HAPPEN!
This metal remembers it’s original shape when it is heated. The particles inside the metal know whose hands they are supposed to hold and in what pattern. Unless the metal is broken, they will not let go of one another’s hands.
FACT! Scientists have used this special metal to develop a large antenna. The antenna can be folded into a small package and carried into space by a spacecraft. Once in orbit, it is released. The Sun’s heat causes the antenna to open, just like the metal flower we placed in hot water.
NOTE! Once an ordinary metal is bent or stretched, it’s atoms move and form new linkages with one another. When the metal is bent back to it’s old position, it retains it’s links due to the new atomic bonding pattern. When a shape memory alloy is bent, the angles between atoms change, but their bonds are maintained. Heating the alloy to a given temperature returns it to it’s original form. Many shape-memory alloys have been developed for industrial and medical use.
Hope you enjoyed this post!!