Multicomponent TiNi-based shape memory alloys : General considerations and selection rules for an initial precursor amorphous state

Abstract
General considerations, which concern the development of new multicomponent shape memory alloys in an initial amorphous state, are discussed. The selection rules for the chemical compositions appropriate for production of both amorphous and potentially shape memory alloys are proposed on a basis of well known three "golden rules" and statements regarding the shape memory phenomena. The production and characterisation of the "AB"-type series amorphous potentially shape memory alloys with "A"=(Ti,Hf,Zr), "B"=(Ni,Cu,Co,Ag,Pd,Al) and the "A:B" ratio varied as 45:55, 50:50 and 55:45 are discussed. The material structure was followed by X ray diffraction and the thermodynamic properties and thermal stability were studied by Differential Scanning Calorimetry. Various heat treatments regimes have been explored for the formation of appropriate microstructures to demonstrate the shape memory property.