Science and Technology Production
Congress
Authorship
La Roca, Paulo
;
ISOLA, LUCIO MANUEL
;
Sobrero, César E.
;
Vermaut, Philippe
;
Malarría, Jorge A.
Date
2014
Publishing House and Editing Place
ICOMAT
Summary
Information provided by the agent in
SIGEVA
The grain size (d) effect on shape memory behavior was investigated by differential scanning calorimetry, four probe electrical resistometry, and light and electron microscopy. Cu-based SMA specimens of various d ranging from about 500 nm (ribbons and tapes obtained by rapid solidification techniques), till single-crystals of 6 mm diameter (grown by the Bridgman method) were prepared by heat treatments in order to modify their grain size condition. The reduction of d shifts the forward transfor...
The grain size (d) effect on shape memory behavior was investigated by differential scanning calorimetry, four probe electrical resistometry, and light and electron microscopy. Cu-based SMA specimens of various d ranging from about 500 nm (ribbons and tapes obtained by rapid solidification techniques), till single-crystals of 6 mm diameter (grown by the Bridgman method) were prepared by heat treatments in order to modify their grain size condition. The reduction of d shifts the forward transformation temperature downwards, and d effects on transformation temperatures and hysteresis are already observed in specimens with d below ~ 100 μm, and became more pronounced for d < ~ 20 μm. The present investigation analyzes the shift in the martensitic transformation temperature by a phenomenological model which takes into account mainly three issues: The contribution to the elastic energy from the constraint introduced by the grain boundaries, a dissipative effect produced by micropasticity and the intervariant boundaries energy.
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Key Words
POLYCRYSTALSHAPE MEMORY ALLOYSCu-BASEDGRAIN SIZE EFFECTS