Akademik Məlumat İdarəetmə Sistemi
Metallofizika i Noveishie Tekhnologii, vol.25, no.12, pp.1553-1562, 2003 (SCI-Expanded, Scopus)
The superplasticity phenomena (i.e. drastic changes of deformation behaviour near the glass-transition temperature, Tg) are the new ways for shaping of the multicomponent TiNi-based shape-memory alloys from precursor amorphous state. Rapidly solidified ribbons are fabricated by the planar-flow casting technique. The material structure is studied by the XRD, TEM/SAD, and SEM techniques; the thermodynamic properties are tested by DSC; the mechanical properties are measured under tension at the room temperature and above. Different initial structural states (totally amorphous or mixture of the amorphous and crystalline phases) are obtained in these ribbons. Those ribbons demonstrate the high shaping ability near Tg. The glass-transition temperature, crystallization temperature, Tx, and heat of crystallization are determined by DSC measurements for all ribbons. The evolution of the structure (nucleation and growth of the crystalline grains during the heating) is studied by the XRD and TEM investigations. The changes of deformation pattern from inhomogeneous (where the all strain is localised in a small volume of the material) to the homogeneous one are determined near Tg. Effects of the temperature and deformation rate on the deformation behaviour of (Ti, Hf, Zr)(Ni, Cu)-based ribbons are discussed.