Suitability of Nickel-base Shape Memory Alloys for Selection and use in Sensing Applications

In the prevailing era, an influential shape memory alloy (SMA) nitinol has emerged as a potentially viable and economically affordable material that is capable of playing a significant role in both existing and emerging technological applications spanning the domains of aircraft and aerospace, biomaterials in bioengineering, sensors in health monitoring, advanced manufacturing, and microelectromechanical systems (MEMS), to name a few. A high strain recovering capability coupled with superelasticity are two key and essential characteristics of a “smart” material that distinguish it easily from its conventional counterparts. The phase transformation behavior shown by nitinol (NiTi) was found to be governed by intrinsic variations in temperature. In order to obtain the desired application-based functionality of this high performing material, potentially viable approaches include the following: (i) an alteration of its chemical composition, (ii) the addition of ternary elements and quaternary elements, and (iii) the use different processing treatments. These approaches are being constantly studied, carefully and systematically examined and frequently reported in the published literature. In this manuscript, an effort is made to present and discuss several of the recent advances specific to the NiTi-based shape memory alloy applications and its phase transformation behaviour when subject to processing treatments. The influence of compositional variation of the NiTi-based shape memory alloys (SMAs) and even its ternary variants and quaternary variants, coupled with the role and/or influence of different processing treatments on both macroscopic properties and microscopic properties is the focus. The emphasis on increasing the suitability of shape memory alloys (SMSs) for selection and use in a spectrum of sensing-related or sensing specific applications is highlighted and briefly discussed.

Keywords: Compositional variation, NiTi-based shape memory alloy (SMA), Phase transformation behaviour, Processing treatments, Shape memory alloy (SMA).