Abstract

The shape memory effect (SME) refers to the phenomenon of shape recovery in a severely pre-deformed material, but only when a right stimulus is applied. The materials with the SME are called shape memory material (SMM), and typical stimuli include heat, chemical (including water/moisture), light, etc [1]. Right now, the family of SMM has expended significantly, and covers a range of different types of materials, including alloy, polymer and ceramic etc [2-5]. In general, the SME process includes two steps [6]. The first step is to program the piece of SMM into a temporary shape (known as the programming process); and the second step is to apply the right stimulus for recovery (called the recovery process) with or without constraint applied.