Shape memory alloys are more and more used in many fields of mechanics and medicine. The reason of the success is the ability to recover the initial shape also after high values of deformation. During the deformation, the SMA are able to change the structure from an initial structure, often named as austenite, to a final structure named martensite. Neither austenite and martensite are the same of the equivalent structures of iron alloy, bit it is only a convention. That transformation takes place a low temperature, and no recrystallization occurs, but the bulk of grains is interested by the structure changing. For that, this phenomenon can't be qualified as a traditional structure transformation, but it is much more correct talk about the transition of phase. The transition Austenite-Martensite is reversible allowing a perfect recover of the shape shown in the austenite phase. In this work a model able to describe the microstructure evolution related to the mechanical behaviour of a SMA has been proposed. Results of FEM simulations have been compared with experimental results both in terms of microstructure modifications and in terms of mechanical behaviour.
Cycling model for a NiTi shape memory alloy
Di Cocco V.
;Bellini C.;Iacoviello F.;Mocanu L. P.;
2021-01-01
Abstract
Shape memory alloys are more and more used in many fields of mechanics and medicine. The reason of the success is the ability to recover the initial shape also after high values of deformation. During the deformation, the SMA are able to change the structure from an initial structure, often named as austenite, to a final structure named martensite. Neither austenite and martensite are the same of the equivalent structures of iron alloy, bit it is only a convention. That transformation takes place a low temperature, and no recrystallization occurs, but the bulk of grains is interested by the structure changing. For that, this phenomenon can't be qualified as a traditional structure transformation, but it is much more correct talk about the transition of phase. The transition Austenite-Martensite is reversible allowing a perfect recover of the shape shown in the austenite phase. In this work a model able to describe the microstructure evolution related to the mechanical behaviour of a SMA has been proposed. Results of FEM simulations have been compared with experimental results both in terms of microstructure modifications and in terms of mechanical behaviour.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
