Shape Memory Behavior in Some (Ti,Zr,Hf)₅₀(Ni,Cu)₅₀ Alloys Elaborated by Glass Devitrification

Abstract:

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 – Tg 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.

• Periodical: Advances in Science and Technology (Volume 59)
• Pages: 113-118
• DOI: https://doi.org/10.4028/www.scientific.net/AST.59.113
• Online since: September 2008
• Authors: Victor I. Kolomytsev, M. Babanly, Alexandre Pasko, A.P. Shpak, Tetjana Sych, P. Ochin, Philippe Vermaut, Richard Portier, Eduard Cesari, D. Rafaja
• Keywords: Amorphous Alloy, Martensitic Transformation (MT), Metallic Glass, Rapid Solidification, Shape Memory

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