A long sequence of thermo-mechanical treatments are required to manufacture NiTi shape memory alloy components starting from NiTi shape memory alloy ingots.

It is known that stress, drawing and annealing can strongly affect the shape and texture of NiTi micro-grains, change the concentration of dislocations and grain boundaries, induce twinned martensite and promote the precipitation of several compounds. NiTi shape memory alloy components functional properties derive from NiTi microstructure.

In the present paper the effects of thermo-mechanical treatments on the microstructure of NiTi wires at different processing and training steps have been investigated by transmission electron microscopy (TEM). Information on the microstructural and crystallographic changes associated to different processing routes drove the improvement of material performances, in view of its application in actuators and smart devices.