Property Database on Shape Memory Alloys for Engineering Design

Abstract

Shape memory alloys (SMAs) as functional materials have many unique characteristics that are quite different from traditional engineering materials. They require an entirely new philosophy of engineering and design. The most fundamental descriptors of property are transformation temperatures, recovery stress, and stress rate rather than yield strength, modulus, and ductility for engineering materials. A particular feature of SMAs is that their properties are very sensitive not only to the intrinsic parameters, such as alloy system, composition, and lattice structure, but to the external conditions, namely, thermomechanical treatments, training history, working environmental temperature, etc. Any minor change of these parameters may largely influence the behavior of an SMA. This has been taken into account when representing and evaluating SMA properties. Published data for SMAs have been collected and evaluated with the emphasis on transformation temperatures, stress rate, recovery stress, recovery strain, and superelastic behavior as well as their changes with thermal and stress cycling. Some engineering design principles are discussed for different application categories that are defined by their SMA functions. Furthermore, a user interface that allows easy access to the properties and related metadata is described.