Uses of Nitinol
Nitinol has many uses, but most commercial uses are currently in the medical field. Medical uses include orthodontic archwires, stents, tubing, files, needles, and some other equipment. For most of the equipment, it is used because it has a high fatigue resistance, and is not very prone to breaking, or because it can bend itself to its original shape with large force. In the case of orthodontic wires, Nitinol is used because it can be set to an ideal shape, cooled briefly, and inserted into the patient's mouth and brackets while cold. Once it heats up to body temperature, it will exert a constant force as it tries to return to the perfect shape, thus pushing the patient's teeth together. In stents, it is used because it can be inserted into veins or arteries without extensive surgery, and then as it heats up, the mesh, like in the picture below, will bend out and expand, holding the vein open to prevent a blockage.