Transformation behaviors and shape memory characteristics of Ti-45Ni-5Cu alloy
ribbons fabricated by melt spinning were investigated by means of optical microscopy,
differential scanning calorimetries(DSC), X-ray diffraction and thermal cycling tests under
constant load. They depended largely on temperatures of liquid metal. The B2-B19-B19
two-step transformation occurred in the ribbons fabricated with the liquid whose temperature
was higher than 1723 K, while the B2-B19 one-step transformation occurred in the ribbons with
the liquid at 1673 K. The stabilization of the B19 martensite in Ti-45Ni-5Cu alloy ribbons was
ascribed to the high density of dislocations which made strong resistance to large lattice
deformation associated with a formation of the B19 martensite.
Experimental investigations on the effect of copper on the microstructure and shape memory characteristics of NiTi alloys