A model for elastic precursor waves in the shock loading of polycrystalline metals

The Use of Ultrasound in the Determination of Microstructure: A Review

The upper 3–5 mm of rail becomes severely cold worked with the regular passage of trains. Previous work has shown that the shear wave velocity in this upper layer is actually reduced by ∼ 10%. One of the most likely sources of this velocity reduction is the presence of a material texture in the upper region. In order to investigate the wave propagation properties of this upper region, several wafers of material, ∼ 4 mm thick, were removed from used and new rail. These wafers were removed from positions at different orientations relative to the longitudinal axis of the rail. Each wafer was secured in a device that permitted a 350° rotation of a pair of shear wave transducers propagating through the thickness of the samples. Transducer centre frequencies were above 10 MHz. The observed shear wave velocity change is compared to predicted changes for several textures observed in steel. A pattern exists indicating that a texture does exist in the cold-worked layer. Steel used for rail normally has a ca...

Ultrasonic studies of anisotropy in cold-worked layer of used rail

A simple, rapid method for the nondestructive evaluation of texture in metal sheet of arbitrary thickness is presented. The method uses a recently developed technique to generate and receive Rayleigh waves on thick plates or Lamb waves on thin materials. The correlation of Rayleigh wave velocity data with calculated values based on elastic constant measurements and with X-ray pole figures is discussed in detail. The technique is applied to a variety of commercially important materials and geometries by the generation of “ultrasonic pole figures.”

G. A. Alers

Papers

An acoustic surface wave method for rapid, nondestructive texture evaluation