Brief Overview of Functionally Graded NiTi‐Based Shape Memory Alloys

Abstract

Shape memory alloys (SMAs) are kinds of smart materials that have superior properties such as shape memory effect and superelasticity, which have the most potential applications in various fields, especially in aerospace, naval, automobile and biomedicine industries, etc. Nevertheless, the inherent natures of shape memory alloys are characterized by the smaller transformation temperature intervals and transformation stress intervals, which make the devices have poor control ability. To achieve the accurate controllability for progressive movement, creating functionally graded shape memory alloys has been adopted. Herein, the classification, fabrications, microstructural features, and performances of functionally graded shape memory alloys are reviewed. For comparison, the creation of various gradients in shape memory alloys can widen the transformation temperature intervals and transformation stress intervals to some extent. In addition, the formation of the compositional, microstructural, or geometrical gradient also contributes to the generation of excellent performances such as the four‐way shape memory effect, higher strength, and larger temperature window for the stress‐assisted two‐way shape memory effect, etc. Such superior functions promote a wider application range of shape memory alloys.

A fast actuated soft gripper based on shape memory alloy wires

“…Currently, the main actuation methods include traditional forms of pneumatic, hydraulic and electric, as well as intelligent forms of piezoelectric [17,18], dielectric elastomers [19][20][21][22], SMAs [23][24][25][26] and magnetorheological fluids [27,28]. Among them, SMA as the intelligent material with the best memory performance among metal materials is integrated with sensing and actuation [29,30]. In addition, it has high power ratio, low noise, corrosion resistance and other properties, and is favored in the intelligent design of actuators [31].…”

Low‐Velocity Impact Response Analysis of Functionally Graded Piezoelectric Plates Using Finite‐Element Method and a Two‐Degrees‐of‐Freedom Spring‐Mass Model

“…[ 2 ] Numerous investigations have been conducted to study the static, dynamic, and vibration responses of FG and FGP structural elements, such as beams, shells, and plates subjected to different loading conditions. [ 3–27 ] The impact behavior of FG plates, composed of ceramic and metallic phases, has spurred notable interests among scholars in the recent years. Gunes and Aydin [ 28 ] studied the effects of physical and geometrical parameters on the elastic impact response of FG circular plates and underscored the influence of the volume fraction of constituent components on the contact behavior and damage region characteristics of the plates.…”