Compact Thermomechanical Testing System for Shape Memory Alloys

Shape memory alloys are smart materials that demonstrate a controllable and reversible behavior due to an external thermal or mechanical stimuli. These materials exist in two distinct phases: a low-temperature phase known as martensite and a high-temperature phase called austenite. When influenced mechanically or thermally, shape memory alloys can revert to their original shape after experiencing pseudoelastic deformations. These materials find applications as actuators, vibration dampeners, and in various medical devices. In this study, we developed a cost-effective, miniaturized thermomechanical testing system that leverages Internet of Things (IoT) technology to investigate the mechanical properties of shape memory alloy structures. We validated the stress-strain curves obtained from cyclic tensile tests under varying thermal conditions using a professional-grade mechanical testing equipment. Optimization of our setup was achieved using Nickel-Titanium alloy (Nitinol) samples as a standard. This bench-top design incorporates microcontrollers to automate the measurement process, manage variables, log data, and display real-time calibrated curves, enhancing the efficiency and accuracy of the testing procedure.