Investigations on the actuation behaviour of friction stir–welded nickel titanium shape memory alloy using continuous fibre laser

Abstract

The friction stir welding (FSW) is found to be an effective solid-state process to join Nickel Titanium (NiTi) shape memory alloy. The retention of shape memory effect has enabled the welded NiTi alloy to be exploited in various functional applications. In this article, the NiTi sheets of 1.2 mm thickness are welded using FSW. The tool selection, geometry design and process parameters required to weld NiTi sheets are explored. Interestingly, an attempt is made to actuate the welded NiTi alloy, using laser actuation technique. The laser beam is scanned over the sample at a particular speed, enabling the increase in temperature suitable for physical actuation. A minimum and maximum displacement of 10 mm and 28 mm are recorded for the laser powers of 10 W and 50 W, respectively. Apart from laser actuation, the dynamic mechanical analysis of the welded NiTi alloy is investigated.

A Review on Present Status of Friction Stir Welding of Nitinol, a Functionally Advanced, Versatile and Widely Used Shape Memory Alloy

“…Though the damping capability of the welded samples are bit lower than the parent samples, all welded samples exhibited good damping capabilities in the verified frequency value of (1, 10 and 20 Hz.) [49]. Even the cyclic load-deformation behavior for FSW-ed NiTinol was tested using a tensile cycle loading test.…”

“…Improved actuator movement was achieved by laser actuation rather than electrical actuation. The FSW-ed strips were actuated in a cantilever arrangement with the help of the laser heating method [49]. Laser actuation offers better actuation capability and a higher value of displacement than electrical heating because of the produced high temperature and impulsive nature of heating.…”