WE Colloquium: Dr. Stanislav Rokhlin, Characterization of polycrystals by ultrasonic scattering

Abstract

Due to thermo-mechanical processing of structural materials they develop complex microstructures with macro and microtextures of nonequiaxed grains. In some materials, such as titanium, orientation clustering of crystallites often occurs (microtextures). Size and level of microtextures may significantly alter mechanical properties of materials and their service life. Ultrasonic scattering in polycrystals depends on the length scale of the grains and their preferred orientation, so ultrasonic characterization may provide nondestructive means to determine the different aspects of material microstructure and anomalies important for material serviceability. This presentation overviews recent theoretical and experimental results for characterization of polycrystalline microstructures from measurements of ultrasonic attenuation, backscattering and velocities. The developed scattering methodology allows to implement a model-based inverse approach that targets determination of all critical microtexture parameters from the ultrasonic measurements without prior knowledge of material properties.

Bio

Stanislav I. Rokhlin is a Professor Emeritus in the Department of Materials Science and Engineering at The Ohio State University. He joined the OSU faculty in 1985 and retired from teaching in summer 2015.
His current research interests are in the experimental and modeling areas of wave propagation and scattering with applications to nondestructive characterization and imaging of inhomogeneous and anisotropic materials, and in interphase mechanics and environmental degradation and failure. He has several patents, has authored over 200 journal publications; his book “Physical Ultrasonics of Composites” was published in 2011 by Oxford University Press. Dr. Rokhlin‘s research has been recognized by numerous professional awards.