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Can one morph a wire by electrical current into a shape different than static shape at beginning? As in the beginning shape being in a spiral, then when electrical energy is passed through the wire it becomes straight. When the current is shut off it would return to a spiral shape as in the beginning form. OR vise versa?

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2 Answers 2

Shape memory materials change shape when heated, regardless of the source of heat, and don't have much directly to do with electricity.

More direct control of shape is possible, but in a very limited form. An open coil will contract when current is passed through it, the magnetic field squeezing the turns together. The magnetic field produced by a very high current will "inflate" a loop of wire into a circle, at high enough currents the generated fields can even stretch or break the coil. These are extreme conditions typically only produced in machines like coin shrinkers, which are themselves another example.

A similar technology is used in some electromagnetic dent pullers and electromagnetic forming. A pulsed magnetic field induces eddy currents in a sheet of metal and then uses those currents to pull the sheet metal into shape. This is of rather limited use in making "shape morphing" objects, however.

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There exist materials very similar to what you are describing called shape-memory alloys. Nitinol, an alloy of nickel and titanium, is one common example. They are deformable, but when they are heated (e.g. with an electric current), they return to a preset shape. They've got industrial applications, but I've also used them in science demonstrations for children and they're usually a big hit. You can see an example of such a material in action here.

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I have just read Mr. Hiroshi Sato, "Development of multifunctional wire that combines shape-memory alloy to piezo electric material" In it his remarks about the material used in piezo movement. My question is aimed at a bent wire becoming straight upon being charged with millivolts. –  dg1enigma Nov 30 '12 at 23:35

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