Ultrasonics for Microcrystalline Structure Examination [and Discussion]

• Published in: Philosophical transactions of the Royal Society of London. Series A: Mathematical and physical sciences 1986-11, Vol.320 (1554), p.161-169
• Main Authors: Goebbels, K., Thompson, R. B., Green, R. E., Briggs, G. A. D., Sayers, C. M., Scruby, C. B.
• Format: Article
• Language: English
• Subjects: Analysing. Testing. Standards; Applied sciences; Backscattering; Birefringence; Construction materials; Exact sciences and technology; Grain size; Material properties; Materials; Measurement of properties and materials state; Metals. Metallurgy; Moduli of elasticity; Nondestructive testing; Residual stress; Ultrasonics
• ISSN: 1364-503X; 0080-4614; 1471-2962; 2054-0272
• DOI: 10.1098/rsta.1986.0107

Non-destructive testing (NDT) methods are used to determine the ability of materials and components to withstand applied loads of different kinds. Besides defects, materials' properties are the interesting features from the engineering point of view. But although defect parameters of materials can be determined quantitatively by NDT, the mechanical-technological parameters cannot be measured directly. They are related to the structure of the materials by different types of multi-parameter dependencies. Ultrasound interaction with the structure can be measured by adjusting the ultrasonic wavelength to the linear dimension of the interesting structural parameter. A second advantage of ultrasonics is the great amount of information about the microstructure obtained by the frequency-dependent measurable quantities: velocity, attenuation, absorption and scattering. The determination of different structural features in this way enables their correlation with the wanted technical materials' properties to be investigated. This contribution discusses, in particular, the following aspects: velocity depending upon microcrystalline features as higher-order effects, leading to correlations with materials properties; scattering as the information parameter about microstructures integrally while describing microcrystalline features locally; independent absorption measurements for the description of microcrystalline structures; interdependence of velocity and attenuation, via the Kramers-Kronig relation.