Shape memory alloys: properties and engineering applications

Abstract

Shape memory alloys (SMAs) are a promising class of advanced materials with interesting properties, which make them suitable for a variety of engineering applications. The uses of SMAs in engineering applications have extended year by year. SMAs are being used in a number of industrial applications such as aerospace, automotive, biomaterial, chemicalsensor, construction, electronics, metal forming, storage and retrieval of information, optics etc. This paper highlights some of these engineering applications of SMAs. This also includes the recent research on the possible use of SMAs in smart structures. The important properties of SMAs that provide the impetus for using these materials in innovative applications are (i) shape memory effect, (ii) pseudoelasticity and (iii) high damping capacity. For a better appreciation, some of the basic principles and properties related to the unique behaviour of this class of materials are also discussed.

Decade of bio-inspired soft robots: a review

“…SMAs are a distinct class of alloys equipped with the ability to memorize [3]. The martensite and austenite are the two states of SMA that transform into one another upon the temperature transition with varying compositions having shape memory, super-elastic, super-thermic, rubber-like, re-orientation, and high damping effects [16][17][18][19] Because of these effects and higher force to weight ratio, low weight, noise-less actuation makes SMA wires ideal fit for soft robotic applications and are widely used in other engineering applications. The SMA wires contract on heating and expand otherwise and this cycle goes on, providing the actuation or locomotion specific to applications.…”

An Intermetallic NiTi-Based Shape Memory Coil Spring for Actuator Technologies

“…Shape memory alloys (SMAs) are broadly used in the development of thermostatic and electromechanical actuators, to perform mechanical actions assisted by temperature change phenomena via electric currents. To improve the robustness, the compact and straightforward design strategy was usually adopted [9][10][11]. Amongst various type of SMAs, nickel-titanium (NiTi)-based SMAs (commonly known as NiTi) are preferably used in most smart engineering structures and actuator technologies due to their exceptional thermo-mechanical performances, practicability, shape memory characteristics, and pseudoelasticity [12][13][14][15].…”