Rayleigh-Like Reflection of Ultrasonic Waves at a Liquid-Solid Layer-Solid Interface.

摘要

An ultrasonic beam in a liquid is incident upon a solid coated with a thin solid layer. At certain angles of incidence leaky surface waves are excited on the interface. These surface waves cause the reflected beam to be separated into two components: the specular component and a displaced component. A schlieren system is used to observe the two components and the null strip between them. The null strip is used as a measure of the angle of excitation of the surface waves, and hence as a measure of the surface wave velocity. The substrates studied were stainless steel, aluminum, lead, plexiglass, brass, glass, copper, and aluminum oxide. The layers were zirconium oxide, aluminum oxide, aluminum, brass, stainless steel, copper, and nickel. The behavior of the phase velocity of the Rayleigh-like waves is determined by the relationship between the layer and the substrate shear velocities.