Effect of ultrasonic vibrations on interface strength in composites of shape memory alloy with metallic matrix

Abstract
The main problem in developing the composite materials containing Shape Memory Alloy (SMA) actuators is to provide the strength of interface between matrix and SMA. The other important problem is to provide the martensitic transformation with needed parameters and resistance to thermal cycling in the composite material. Application of ultrasonic (US) technologies for obtaining composite materials helps to some extent to solve the above-mentioned problems. The ultrasonic technologies available are the composite materials crystallization in ultrasonic field, simultaneous deformations of composite components by using ultrasound and sintering of powdered/fractured composite mix with high-intensity ultrasound apply to different stages of the process. All these are aimed at obtaining the composites with good functional properties. In the present paper, main attention is paid to the composite materials consisting of the CuAlNi, CuAlMn, CuAlZn and Ni-Ti shape memory alloys and various second component (aluminum, copper and Cu-alloys), Two main achievements have been reached by application of the US vibrations: modification and refinement of the shape memory alloy microstructure; improvement in adhesion of the superelastic/shape memory materials to the metal substrate surface subjected to ultrasonic metallisation.