An experimental analysis on the influence of CO2 laser machining parameters on a copper-based shape memory alloy

Abstract

The term 'shape memory alloys' (SMAs) refer to a group of metallic materials that have the ability to return to a previously defined shape when subjected to the appropriate thermal or loading cycles. They are now being employed in different real-life applications. Cu-Al-Fe is a High Temperature Shape Memory Alloy (HTSMA) and could replace Ni-Ti SMAs. Conventional machining technologies are not efficient enough in machining SMAs, and thus the properties of the SMAs are affected. One of the most successful technologies for processing these alloys is Laser Beam Machining (LBM). This work shows an investigation of the effect of process variables in laser machining on SMA. Differential scanning calorimetry, X-Ray Diffraction, Optical Microscopy, Scanning Electron Microscopy, and Hardness tests were used to analyze the laser-machined material. It has been found that power was the highest influencing variable which affects Material Removal Rate (MRR) and Surface Roughness (Ra), and the second most influencing parameter was cutting speed. DSC thermograms confirm that the Shape Memory Effect (SME) and the transition temperatures of the SMA have not been much affected after machining. The hardness of the machined surface slightly increased after machining, owing to the formation of a re-solidified layer.