Nonlinear acoustics in studies of structural features of materials

• Published in: MRS bulletin Vol. 44; no. 5; pp. 350 - 360
• Main Author: Zaitsev, V.Y.
• Format: Journal Article
• Language: English
• Published: New York, USA Cambridge University Press 01.05.2019; Springer International Publishing; Springer Nature B.V
• Subjects: Acoustic Processes in Materials; Acoustic properties; Acoustics; Applied and Technical Physics; Characterization and Evaluation of Materials; Chemical composition; Cracks; Crystal defects; Crystal lattices; Crystal structure; Defects; Diagnostic software; Diagnostic systems; Elastic properties; Energy Materials; Materials Engineering; Materials Science; Microscopy; Modulus of elasticity; Nanotechnology; Nondestructive testing; Nonlinearity; Organic chemistry; Ultrasonic imaging; acoustic; fatigue; microstructure; defects; fracture
• ISSN: 0883-7694; 1938-1425
• DOI: 10.1557/mrs.2019.109

Linear elastic moduli of solids with similar chemical compositions usually vary fairly insignificantly. However, for a broad class of apparently similar materials, their higher-order (nonlinear) moduli may differ by many times or even by orders of magnitude. Besides their large magnitude, nonlinear effects often demonstrate qualitative/functional features inconsistent with predictions of the classical theory of nonlinear elasticity based on consideration of weak lattice (atomic) nonlinearity. The latter is mostly applicable to ideal crystals and flawless amorphous solids, whereas the presence of structural heterogeneities can drastically modify the acoustic nonlinearity of materials without appreciable variation in the linear elastic properties. Despite often rather nontrivial/nonstraightforward relationships between microstructural features of the material and the resultant “nonclassical” acoustic nonlinearity, the extremely high structural sensitivity makes utilization of nonlinear acoustic effects attractive for a broad range of diagnostic applications that have been emerging in recent years in various areas—from seismic sounding and nondestructive testing to materials characterization down to the nanoscale.