Influence of graphene nanoparticle mixed EDMD on the phase transition behaviour and surface characteristics of nitinol SMA

Nitinol (NiTi) shape memory alloy (SMA) is a unique nickel-based alloy which has been widely used in the medical and aerospace industries because of its shape memory effect. The phase transition temperatures of NiTi SMA have been responsible for its shape memory effect. The current work inspected the effect of the graphene nanoparticle added electrical discharge micro drilling (EDMD) process on the phase transition behaviour of nitinol along with the impact of various EDMD settings on the 3D surface topography and surface morphology. The temperature hysteresis from the differential scanning calorimetry (DSC) results significantly reduces the R phase starting temperature by 9°C. It shortens the thermal hysteresis and enhances the thermal stability of NiTi. It can be beneficial for controlling the SME of NiTi SMA, which enhances its flexibility of design in terms of micro-parts in various industries. The current research outperformed the existing literature study through the reduction of thermal hysteresis by 15°C to 34°C. The employment of graphene particles reduces the S a , S q , and S z by almost 50% to 80% and improves the surface texture of the machined sample for different sets of DE. Superior mirror-like surface finish has been obtained at low discharge energy.