Mechanical and functional properties of amorphous–crystalline thin ribbons of Ti50Ni25Cu25 and Ti40.7Hf9.5Ni44.8Cu5 shape memory alloys

Amorphous melt spun ribbons of Ti50Ni25Cu25 and Ti40.7Hf9.5Ni44.8Cu5 alloys were partially crystallized to different volume fractions of the crystalline phase from 0 to 100%. The mechanical and functional properties of amorphous–crystalline thin ribbons were studied. It was shown that the fully amorphous sample of Ti50Ni25Cu25 alloy was deformed elastically up to 2.2% and then it was deformed plastically up to breaking. The fully amorphous sample of Ti40.7Hf9.5Ni44.8Cu5 alloy was deformed elastically up to failure and plastic deformation was not observed. It was found that amorphous–crystalline samples demonstrated the shape memory effect on heating. The maximum recovered strain was 3.3% in fully crystallized Ti50Ni25Cu25 alloy and it attained 5% in Ti40.7Hf9.5Ni44.8Cu5 alloy. The Ti40.7Hf9.5Ni44.8Cu5 alloy demonstrated the two-way shape memory effect if the amorphous and crystalline phases co-existed in the sample. (fast track communication)