The conventionally produced Ti 50 Ni 50−x Cu x shape memory alloys with Cu-content exceeding 12at.% have been reported to be brittle. The authors have recently reported that, after being properly annealed, the Ti 50 Ni 25 Cu 25 melt-spun ribbon exhibits excellent superelasticity and shape memory effect. The present research aims to elucidate why these beneficial properties come about by investigating the evolution of microstructures and textures as a function of the annealing condition. It is found that annealing at 500°C and above results in the formation of a strong (111)[7¯15]B19 sheet texture that is favorable to martensite detwinning, while with annealing at 550°C and above the formation of B11 precipitates becomes significant. These two factors are believed to play key roles in determining the properties of the ribbon.