A review on machining of NiTi shape memory alloys: the process and post process perspective

Nickel–titanium (NiTi) shape memory alloys have gained more prominence due to their functional and mechanical properties. This material undergoes solid-state phase transformation during machining. Together with this, inherent properties of this material result in challenging machinability behaviors such as excessive tool wear, high cutting forces, and degraded surface integrity. Furthermore, unique stress–strain curve of this material complicates predicting machining behaviors. This paper reviews research in the machining of NiTi shape memory alloys carried out over the last 20 years with the objective of assessing overall machinability characteristics. It is concluded that functional properties and machinability responses of NiTi are very sensitive to machining parameters and environment. Machinability rate of NiTi should be assessed not only by usual machinability measures (i.e., tool wear, cutting forces, surface integrity) but also by considering post machining functional behaviors.