Shape Memory Alloys

The Shape Memory Alloys (SMAs) represent a unique material class exhibiting peculiar properties like the shape memory effect, the superelasticity associated with damping capabilities, high corrosion and extraordinary fatigue resistance. Due to their potential use in an expanding variety of technological applications, an increasing interest in the study of the SMAs has been recorded in the research community during the previous decades. This book includes fundamental issues related to the SMAs thermo-mechanical properties, constitutive models and numerical simulation, medical and civil engineering applications and aspects related to the processing of these materials, and aims to provide readers with the following: It presents an incremental form of a constitutive model for shape memory alloys. When compared to experimental tests, it proves to perform well, especially when the stress drops during tension processes. It describes single-crystal and multi-grained molecular models that are used in the dynamic simulation of the shape memory behaviour. It explains and characterizes the temperature memory effect in TiNi and CU-based alloys including wires, slabs and films by electronic resistance, elongation and DSC methods. It analyses the thermo-mechanical behaviour of superelastic NiTi wires from low to impact strain rates, including the evolution of the phase transformation fronts. It presents an experimental testing programme aimed to characterize the bending deformation and the fatigue properties of precision-casted TiNi SMA used for instruments in surgery operations. It introduces a computational model based on the theory of hysteresis operator, able to accurately characterize the non-linear behaviour of SMA actuators and well suited for realtime control applications. It describes the development and testing of an SMA-based, highly sophisticated, lightweight prosthetic hand used for multifunctional upper-limb restoration. It presents the design of an active catheter and endoscope based on shape memory alloy actuators, expected to allow low cost endoscopic procedures. It exemplifies the use of superelastic shape memory alloys for the seismic vibration control of civil engineering structures, considering both passive and semi-active devices. It discusses some aspects related to the processing of the shape memory alloys and presents special techniques that provide bonds without severe loss of the initial SMA properties. With its distinguished team of international contributors, Shape Memory Alloys is an essential reference for students, materials scientists and engineers interested in understanding the complex behaviour exhibited by the SMAs, their properties and potential for industrial applications.