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.