Abstract
The functional characteristics (actuation force, movement) of an actuator based on a shape memory alloy (SMA) depend
strongly on the specific properties (transition temperature, degree of shape recovery) of the used alloy in order to making
the actuating element. Development of new SMA or improving of those becomes “classical” lead to the achievement of
some more performant actuators based on SMA-s. The paper presents two polycrystalline alloys having shape memory
effect (SME), belonging to the Cu-Al-Ni system, with compositional range between (12.2-13.5)% Al, (3.3-3.5)% Ni, balance
Cu, modified by alloying with small quantities of Mn and Ti. The study of these alloys aims to carry out some thermal
actuators designed to function in 20-80°C temperature range. The structure investigation of alloys was performed by optical
methods, while mechanical characterization was performed by tensile tests. Direct and reverse martensitic transition
temperatures were evidenced by thermal analysis: electrical resistivity dependence on temperature, and dilatometrical
analyse in 20-200°C temperature range. The obtained results show that small Mn and Ti additions inserted in the
composition of studied SMA lead to improving the alloy’s structure and to an important modification of the critical
temperatures to the functional thermal domain of proposed actuator.
Keywords
Shape memory alloy, Cu-Al-Ni, Martensite, Critical temperature, Thermal analysis.
Citation
V. DOBREA, M. LOZOVAN, S. STANCIU, Cu-based shape memory alloy for thermostatic actuator device, Optoelectronics and Advanced Materials - Rapid Communications, 3, 9, September 2009, pp.964-968 (2009).
Submitted at: July 1, 2009
Accepted at: Sept. 15, 2009