Design and Material Evaluation of Shape Memory Composites

Abstract

Shape memory alloy (SMA) is regarded as one promising intelligent material element natively with thermo-sensor, shape memory actuator functions. A fundamental design concept for intelligent materials using SMAS is firstly proposed. Two types of composites which show some intelligent functional properties relating to the shape memory phase transformation were fabricated. One is the shape memory TiNi fiber/Al matrix plate. Another is the plaster matrix composite as a model of building material which contains both shape memory TiNi fibers and high damping TiNi particles having different phase transformation temperatures with each other. The former (TiNi)f/Al composite showed unique properties such as self-strengthening by the compressive stresses in Al matrix due to shape memory shrinkages of the embedded TiNi fibers. The increases of tensile property (yield stress) as well as fatigue resistance (crack growth retardation) at higher temperature were experimentally confirmed. The latter (TiNi),f/plaster showed the increases of resistance to fracture as well as vibration damping.