NiTiCu alloys are one of the most commonly investigated shape memory alloys (SMA) because of their superior performance as SMA actuators [1]. The most commonly used procedures for identifying the degradation that a SMA undergoes with thermomechanical cycling are uniaxial tension tests at constant stress with thermal cycling or isothermal tests at a certain strain level [2]. These tests provide high-value information that enables the simplest models to be made for the thermomechanical response of these materials [2]. However, SMA actuators do not always work under tension loads and these tests do not provide all the information required to characterize their behaviour [3]. Therefore, for better characterization and modeling of these materials is necessary to identify the complete stress/strain tensor. However, these data are largely lacking in the literature, which means that certain typical modeling assumptions need to be clarified, such us the constant transverse to axial strain ratio or symmetric tension-compression behavior that has not been totally contrasted. Other authors have also recently studied these assumptions using digital image correlation [4], neutron diffraction and micromechanical simulations [5,6]. However, most studies are only based on pseudoelastic or superelastic alloys, whereas shape memory effect (SME) alloys, which are useful because they are recovered via moderate temperature increases (actuator purposes), are largely absent from the literature. For these reasons, in this study, a complete characterization of a NiTiCu SME alloy (tube specimens) with stacked strain gauges rosettes has been carried out using tension, compression and torsion tests in order to obtain the complete strain tensor, which enables the study of the tension/compression asymmetry and transverse to axial strain ratio analysis.
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