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Autori: V. Dia, L.G. Bujoreanu, S. Stanciu and C. Munteanu
Editorial: Elsevier, Materials Science and Engineering: A, 481-482, p.697-701, 2008.
The behavior of helical springs made from lamellar specimens of Cu-Zn-Al shape memory alloy, which were martensitic at room temperature, was analyzed in force-elongation-temperature space. The study revealed the dependence of two forms of shape memory effect (SME): (i) work-generating SME and (ii) constrained-recovery SME, upon applied load and elongation, respectively. The tensile behavior of the springs, on loading between the austenite-start and the austenite-finish temperatures showed a stiffening tendency with increasing both elongation and temperature. The lamellar helical springs were able: (i) to lift 3 N loads over 0.235 m with a rate of 7 × 10−3 m/K; (ii) to develop with a maximum rate of 0.6 N/m a recovery force as high as 24 N while being elongated by 0.232 m; (iii) to elongate by 7 × 10−2 m under the effect of a 20 N force applied at 328 K, with an average rate of 342 N/m.
Cuvinte cheie: Shape memory effect; Work generation; Lamellar helical springs; Force-elongation-temperature variations; Variation rate