A case study of experimental evaluation of the properties of shape memory alloy wires

The article presents the development of an original concept of an experimental setup for the identification of the physical properties of shape memory alloy wires. The experimental setup allows performing fast and high-quality real-time testing of SMA wires with different diameters, lengths, and transition temperatures. A screw pair is used to create tension in the test specimen. The wire is heated by applying a direct current to it, and the results obtained for the temperature, the tensile force and deformation of the wire are recorded as a function of time, processed and visualized in a Labview environment. Through a series of experiments, a series of temperature hystereses was obtained and used to determine the transformation temperatures between the martensite and austenitic phases of a wire with a diameter of 0.25 mm. Regression equations describing the dependence of the transformation temperatures on the prestress in the wire are derived. Through additional experiments, the values of Young's modules for the martensite and austenite phases of the alloy necessary for its mathematical modelling were obtained.