Mechanical behavior of shape memory alloys considering the effects of body fluids corrosion for biomedical applications

Shape memory alloys (SMAs) are widely used in biomedical engineering, including cardiovascular stents, artificial skeletons, and orthodontic implants. For the above applications, the body fluids corrosion processes will inevitably cause deterioration in the mechanical properties of the SMAs actuator during its service life, which will threaten the safety of human health. To analyze such problems, experimental measurements have been carried out to investigate the influence of body fluid corrosion on the mechanical properties of SMAs. Changes in the mechanical properties, such as Young's modulus and phase transformation temperatures of SMAs under body fluids corrosion were tested firstly in the simulated body environment with the 0.9 wt. % NaCl solution at 37. With an increase of the immersion time, the results show that the Ti (titanium) percentage, austenitic (reverse) transformation start temperature, austenitic (reverse) transformation finish temperature, and maximum residual strain all increase, the Ni (nickel) percentage, martensitic transformation finish temperature, tensile strength, and yield strength decrease, and the martensitic transformation start temperature first decreases and then increases. The research in this work can provide an experimental basis for further study of the SMAs materials in biomedicine applications.