Akademik Məlumat İdarəetmə Sistemi
3rd International Conference on Smart Materials, Structures and Systems - State-of-the-art Research and Application of SMAs Technologies, CIMTEC 2008, Acireale, Sicily, Italy, 8 - 13 June 2008, vol.59, pp.113-118, (Full Text)
A series of multielementary AB-type shape memory alloys, quaternary (Ti,Hf)50(Ni,Cu)50 and quinary (Ti,Zr,Hf) 50(Ni,Cu)50, have been produced by means of the melt-spinning (ribbons), twin-roll casting (strips) and injection casting (bars) techniques. The glass forming ability (GFA) has been investigated by means of calorimetric studies (DSC, DTA), microscopic observations (TEM/SAD, SEM, XRD, optical microscopy) and deformation tests (bending, tension). The glass transition (Tg) and crystallization (Tx) temperatures with the corresponding supercooled liquid window ΔT = Tx - T g have been determined for the mentioned rapid solidification techniques. GFA is found to be strongly dependent on specific ratio between the constituent alloying elements, with effective element A containing mixture of the early transition elements A = (Ti,Zr,Hf) and effective element B containing mixture of the late transition elements B = (Ni,Cu), respectively. We report a choice of the alloy composition, which is amorphous after fast cooling while recovers a reversible B2 ↔ B19 ↔ B19′ martensitic transformation sequence and demonstrates shape memory and superelastic properties (up to Ms ∼ 400 K, AF ∼ 450 K in the bulk material versus Ms ∼ 250 K, AF ∼ 350 K in the ribbon and strip states) after an adequate thermal treatment. © 2008 Trans Tech Publications, Switzerland.