Experimental analysis of coupled mechanical–electrical behaviour in shape memory alloys

Shape Memory Alloys (SMAs), particularly Nickel–Titanium (NiTi) alloys, have emerged as promising materials for intelligent and robotic systems due to their unique capability to recover their original shape under thermal or electrical excitation. This study presents an experimental investigation and analysis of the coupled mechanical and electrical properties of NiTi SMA, aiming to establish a correlation between phase transformation and electrical response. The experimental procedure combined mechanical tensile testing with electrical resistance measurements performed under controlled temperature and voltage conditions. The results demonstrated that the electrical resistance of the alloy decreased by approximately 12–18% during the transformation from martensite to austenite, while the stress level increased by 8–14% under thermal activation. These findings confirm a strong coupling between the thermal, electrical, and mechanical behaviours of the alloy. The observed interaction highlights the competitive influence of temperature on mechanical stress generation. The outcomes of this work provide essential insights into the design and optimisation of SMA-based actuators and sensors. Moreover, the established correlation between electrical response and phase transition can support the development of adaptive control strategies for SMA-driven robotic mechanisms, enhancing their reliability, efficiency, and overall system performance.