Impact of Different Electrical Time-Based Activations on NiTi Shape Memory Alloys

Abstract

The use of NiTi shape-memory alloys (SMA) in actuators bears significant advantages for designing robust, simple and lightweight applications. The SMA effect is based on a phase transformation of the atomic lattice in response to stress, strain and temperature. The resulting crystallographic configurations lead to a complex behavior revealing different electrical and mechanical characteristics. In view of the impact of thermo-mechanical cyclization on the operational lifetime, this paper investigates the influences of different types of electrical activation. For this purpose, six current curves with six samples each are compared to a reference activation with regard to the operational lifetime. The chosen time of activation is 1 second in accordance with an industrially relevant cycle of technical actuators. Based on the results of these investigations, recommendations of the activation type shall be developed for the operational lifetime of NiTi-SMA.