Influence of Guinier-Preston zones on deformation in Ti-rich Ti-Ni thin films

The deformed microstructure of a Ti-48.9at.%Ni thin film has been investigated by transmission electron microscopy. It was found that Guinier-Preston (GP) zones exist in the thin film and the martensite has (001) compound twins as substructure. The microstructure of the martensite shows that the GP zones do not stop both the shear deformation of martensitic transformation and the twinning shear of (001) deformation twin in the martensite phase. These results give a microstructural explanation for the previous result that Ti-rich Ti-Ni thin films with GP zones show a large transformation strain despite the presence of the GP zones.