Experimental Investigation and Optimization of Process Parameters in Laser welding of NiTinol Shape Memory Alloys

Abstract

Abstract In this work, an attempt was made to conduct bead on plate welding of NiTinol Shape memory alloy utilizing Yb: YAG laser welding process and identify the optimized parameters using Deng’s Similarity based approach integrated with Entropy Weight Method. Bead on Plate welding was carried out based on L9 Taguchi array with laser power, focal position, shielding gas blown distance and welding speed as input parameters. Bead width (BW), depth of penetration (DOP), microhardness (MH), and corrosion current density were measured as output parameters. Entropy weight method was first utilized to determine the weights that had to be given to output parameter, and Deng’s similarity based approach was used to find the optimized welding parameter combinations. The metallurgical characterization of the optimized weld was discussed with the aid of microstructure. Entropy weight Method results suggested to give more importance to microhardness. Deng’s Similarity approach identified that the 7th experimental (welding speed = 2400 mm/min, shielding gas blown distance = 8mm, focal position= 0.5 mm, power = 900 W) run as the optimized parameter combination for getting the weld with full penetration, lesser bead width, higher microhardness and corrosion resistance