Smart materials and smart structures(1)——Shape-memory materials

In this paper,smart shape-memory alloys(SMA),shape-memory ceramics(SMC)and shape-memory polymers(SMP)are reviewed,including their structures,fabrication methods,characteristics and applications.The shape-memory materials(SMM)exhibit some novel performances,such as sensitivity(to thermal,stress or field),large-stroke actuation,high lamping,self-adaptive response,shape memory and super elasticity capability,which can be utilized in smart system.The basic phenomena in the materials,the stimulus-induced phase transformations which result in the unique performances and govern the remarkable changes of properties of the materials,are described.The barriers and the challenges faced in improving the present materials system and developing more new shape-memory materials are discussed.