| Shape Memory Alloys (SMA's) have the ability to return to a predetermined shape when heated. When an SMA is cold, or below its transformation temperature, it has a very low yield strength and can be deformed quite easily into any new shape--which it will retain. However, when the material is heated above its transformation temperature it undergoes a change in crystal structure which causes it to return to its original shape. If the SMA encounters any resistance during this transformation, it can generate extremely large forces. The most common shape memory material is an alloy of nickel and titanium called Nitinol (50 atom% Ni, 50 atom% Ti). This particular alloy has very good electrical and mechanical properties, long fatigue life, and high corrosion resistance. Information provided by TiNi Alloy Company. MatWeb has a separate entry for the high temperature phase of Nitinol. |
| Titanium Nickel Alloys, SMAs |
