Metallurgical development of shape memory alloy nanocomposites augmented by ZnO and CdO metal oxide nanoparticles for the next gen material applications: a review

Abstract

Shape memory alloys (SMAs) have become one of the most promising families of smart materials because of their high actuation capabilities, superelasticity, and distinctive shape memory effect. Despite these advantages, conventional SMAs still suffer from limitations, such as a sluggish thermal response, functional degradation during cyclic operation, and restricted multifunctional performance. Recent advances have demonstrated that reinforcing SMAs with selected metal oxide nanoparticles (MONPs), particularly zinc oxide (ZnO) and cadmium oxide (CdO), offers a promising strategy for overcoming these limitations through microstructural modification and improved thermomechanical properties. Accordingly, this review critically evaluates the metallurgical development of metallic SMA nanocomposites reinforced with ZnO and CdO nanoparticles. This review specifically focuses on metallic SMAs because of their superior thermomechanical performance and widespread engineering applications. ZnO and CdO are chosen because of their proven capacity to modify the functional characteristics, phase transition behavior, and microstructure of SMAs. This review further examines the strengthening mechanisms associated with nanoparticle incorporation, including grain refinement, interfacial interactions, and defect control, and discusses the challenges related to nanoparticle dispersion, interfacial compatibility, and long-term reliability. A comparative analysis of recent studies indicates that appropriate nanoparticle reinforcement can greatly enhance the overall performance of SMAs, making them attractive candidates for advanced engineering systems, smart actuators and renewable energy technologies. Finally, this review identifies existing research gaps and outlines future metallurgical research directions for developing high-performance SMA nanocomposites with enhanced durability, efficiency, and multifunctionality.