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Numéro
J. Phys. IV France
Volume 01, Numéro C4, Novembre 1991
EUROPEAN SYMPOSIUM ON MARTENSITIC TRANSFORMATION AND SHAPE MEMORY PROPERTIES
Page(s) C4-439 - C4-444
DOI http://dx.doi.org/10.1051/jp4:1991466
EUROPEAN SYMPOSIUM ON MARTENSITIC TRANSFORMATION AND SHAPE MEMORY PROPERTIES

J. Phys. IV France 01 (1991) C4-439-C4-444

DOI: 10.1051/jp4:1991466

MECHANICAL AND ELECTRICAL PROPERTIES OF A NiTi SHAPE MEMORY ALLOY

G. AIROLDI1, 2, T. RANUCCI2 and G. RIVA1

1  I.N.F.M., Dipartimento di Fisica, Universita'di Milano, Via Celoria 16, I-20133 Milano, Italy
2  I.T.M.-C.N.R., Area della Ricerca di Milano, Via Bassini 15, I-20133 Milano, Italy


Abstract
Mechanical properties of shape memory NiTi alloys have been widely investigated : though a reasonable understanding of the micromechanisms underlying macroscopic behaviour is known, these sometimes can hardly be inferred from macroscopic stress-strain curves. Electrical Resistance (ER) measurements, extensively used to investigate thermal martensite, are here performed on NiTi alloys under stress state. Attention is here focused on the mechanical and electrical behaviour of a NiTi alloy in one start single phase : -in martensitic phase, at [MATH] or within the hysteresis cycle ; -in parent phase, at [MATH] or within the hysteresis cycle. ER, sensitively affected by electronic structure modifications, lattice structure defects, residual impurities, can profitably be exploited to enlighten similar macroscopic stress-strain behaviour. ER results here obtained allow to discriminate different active micromechanisms, specifically at a same temperature within the hysteresis cycle where similar stress-strain curves are obtained.



© EDP Sciences 1991