Influence of carbon content on the rotary bending fatigue tests of NiTi SMA wires

Superelastic NiTi shape memory alloys (NiTi SMA) are destined for applications in several areas such as aerospace, robotics and biomedical. In Biomedical applications include stents, orthopedics implants, arc wires and endodontic files for tooth root canal preparation. That last application the endodontic files upon rotation are subjected to both tensile and compressive stress in curved canals and unexpected failure may occur during rotary operation. Due to this problem, rotary bending fatigue tests to analyses fatigue resistance of shape memory wires are necessary. Recent work has shown that the influence of carbon content of NiTi SMA on its rotary bending fatigue resistance is an important factor. Aiming a future application as a raw material to produce endodontic files, NiTi wires produced with various carbon contents will be tested using rotary bending fatigue test varying wire curvature radius and rotational speed. Furthermore, special wire surface finish will be given to the wire in order to enhanceµ the real effect of carbon content on the fatigue resistance on the NiTi wires.