On the deformation of the twinned domain in NiTi shape memory alloys

Owing to its importance in understanding the mechanical and thermomechanica l behaviours of shape memory alloys (SMAs), the deformation mechanism of ma rtensitic twins has been of continuous research interest. Several deformati on steps have been distinguished in accordance with the stress -strain curv es, and some explanations have been proposed on the basis of microstructura l studies. However. various experimental observations have suggested that I t complete understanding of the macroscopic deformation behaviour of the tw inned martensitic NiTi SMAs from a microscopic scale is yet to be establish ed. The present research aims at providing a further insight into the micro structural variations under tension within each deformation stages and tryi ng to correlate these changes to the observed mechanical behaviour. As a re sult, the understanding of the deformation behaviour of NiTi martensite und er tension is refined.