A shape memory alloy undergoes a phase transition changing from one crystal structure to another at a specific temperature. The most common shape memory alloy is Nitinol (Nickel Titanium Naval Ordinance Lab). Variations in the ratio of nickel to titanium create different nitinol characteristics.
Nitinol forms a dark oxide on its surface that protects it from further oxidation, making the wire incredibly durable. However, it can be easily damaged by over-heating, at which point it becomes brittle. You can shape its memory form by heating it. Using a lighter or unregulated current to shape-form nitinol can damage the wire by evaporating nickel from the alloy. It is not necessary to exceed 200º C when forming and shape setting your nitinol.
Thinner nitinol wire with an identical transition phase reacts faster than a thicker wire because it takes longer for it to absorb heat.
Our nitinol is available in transition temperature ranges of 25º C, 40ºC and 80ºC, allowing for a wire range of applications. Available thicknesses range from 0.5mm to 2mm (24 AWG - 12 AWG). Custom temperature range and diameter are available for order. Minimum custom orders start at 1 kilogram of material. Thinner wire costs more per kg due to additional machining expenses.