Glass forming ability and thermodynamic properties of Ti(Zr,Hf)NiCu shape memory alloys

Abstract
Rapidly solidified amorphous and crystalline-amorphous ribbons have been produced from a number of quatemary Ti _50+z-x(Zr,Hf) _xNi _{50- z-y}Cu _y alloys where z =(-5, 0, 5). Structural states were checked by XRD, crystallization behaviour of amorphous phase and martensitic transformations in crystalline material were studied by DSC. The glass transition and crystallization temperatures have been measured at different heating rates, and the crystallization activation energy for each composition and heat event bas been calculated. Isothermal crystallization gives an alternative method of determining the activation energy according to the Arrhenius equation. Contradictory requirements for the conditions of martensitic transformation and good glass forming ability is discussed.