Towards applications, processing and advancements in shape memory alloy and its composites

Abstract

NiTi’s exotic ability to memorize and regain memorized shape through simple triggers makes it an outstanding material with potential to empower growth of modern applications. Applications in earthquake resilient buildings, biocompatible implants devices and instruments, actuators for aerospace, devices for space applications, sensor and actuators are few to cite. The cost of virgin-NiTi suitable as raw materials for manufacturing devices and articles is the major deterrent in the wide adoptability of such products. Composites with NiTi in powder/fiber and other form as reinforcement exhibit comparable properties to virgin NiTi with additional advantages due to thermal coefficient mismatch and shape memory induced internal stresses. The NiTi based composites are being manufactured by several different routes including casting technology, solid-state based powder metallurgy, hot pressing/roll bonding/friction stir processing and several others. NiTi in powder/fiber/ribbon or even sheet form may be reinforced which distinct advantage of each. Each of these routes have issues and merits typical of the process. It will be a great enabler to unveil prominent characteristics of the processes and products so that merits/limitations relationship can be optimized and maximum benefits can be harnessed. This status report highlights the state of the art on NiTi and NiTi based composites and composite fabrication routes, all in one place so that the relevant stakeholder can be benefited most and the new developments on such topics foster.