Advances in Non-destructive Materials Characterization

摘要

Although historically nondestructive techniques have been used almost exclusivelyfor detection of macroscopic defects in structures after they have been inservice for some time, it has become increasingly evident that it is bothpractical and cost effective to expand the role of nondestructive evaluation toinclude all phases of materials production. This paper will briefly describe theCNDE and describe several innovative nondestructive evaluation methods developedthere. Among the topics to be discussed will be pulsed lasers, opticalinterferometers, electromagnetic acoustic transducers (EMATs), and air-coupledtransducers for non-contact generation and detection of ultrasonic and acousticemission waves; high resolution optical holographic interferometry for full-fieldvibration monitoring, leak testing of sealed packages and layup of composites;process control of composite tow placement, evaluation of thick composites;integrity of adhesive bonds; computer assisted tomography imaging of internalstructure of ultralightweight metals; real-time viewing and recording of x-raydiffraction images showing the vibrational modes of quartz crystals, images ofdefects in gallium arsenide crystals and substructure in nickel alloy singlecrystal turbine blades.