Hybrid fiber laser drilling investigations on NiTiCuZr shape memory alloy
C. Balasubramaniyan, K. Rajkumar, V. Sampath, A. Arun
Abstract
The synergistic effect of water jet assistance in fiber laser drilling (WJ-FLD) of NiTiCuZr shape memory alloy (SMA), known for its superior thermal stability, corrosion resistance, and high-temperature shape memory behavior is explored. The copper and zirconium enhance the alloy’s functional fatigue life and thermal performance, making it ideal for applications in biomedical devices, aerospace actuators, and high-temperature environments. However, the drilling of such SMAs poses significant challenges due to their high strength and temperature sensitivity. To address challenges, WJ-FLD is employed to improve circularity of holes and minimize thermal damage. The high-pressure water jet serves to cool the drilling zone, reduce recast layer formation, and assist in debris removal, leading to cleaner and precise holes. Circularity and hole taper angle were evaluated using RSM-CCD to study the influence of frequency (F), laser power (P), and nozzle distance (ND). As F, P, and ND increased, hole taper angle (HTA) decreased by 78.52% and circularity (CR) increased by 17.93%. SEM images show high geometric accuracy of the produced holes in the laser advancing direction. DSC revealed that optimized drilling parameters do not affect shape memory property. By rapidly dissipating heat at the drilling zone, WJ-FLD improves cutting quality and hole integrity.