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Mechanical Engineering Commons

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1993

Other Materials Science and Engineering

Articles 1 - 5 of 5

Full-Text Articles in Mechanical Engineering

Line-Focus Acoustic Mcroscopy Measurements Of Thin-Film Elastic Constants, Jin O. Kim, Jan D. Achenbach Jan 1993

Line-Focus Acoustic Mcroscopy Measurements Of Thin-Film Elastic Constants, Jin O. Kim, Jan D. Achenbach

Review of Progress in Quantitative Nondestructive Evaluation

Thin film materials are widely used as hard, protective coatings for softer surfaces. It is known that fracture strength and hardness are related to the elastic and plastic properties [1]. The elastic constants of the film deposited on a substrate are, however, difficult to measure. By a technique which was recently discussed [2] the elastic constants of amorphous (isotropic) films and single-crystal (anisotropic) films can be obtained by measuring the velocities of surface acoustic waves (SAWs) propagating over a thin-film/ substrate specimen by the use of a line-focus acoustic microscope.


A Reflection Ultrasonic Interference Method For Measurement Of The Acoustic Velocity Of Thin Layers, D. K. Mak, G. Langlois Jan 1993

A Reflection Ultrasonic Interference Method For Measurement Of The Acoustic Velocity Of Thin Layers, D. K. Mak, G. Langlois

Review of Progress in Quantitative Nondestructive Evaluation

Ultrasonic waves can be used to measure the velocities and other properties of a material layer by determining the difference in the time-of-flight of the successive echoes from the backwall of the layer. The top and bottom surfaces must be sufficiently far apart for the successive echoes to be distinct. This method can be used to measure the velocity of a protective epoxy layer on a pipeline wall to determine the deviation of an ultrasonic wave scattered from a defect. It has been used to determine the strength of adhesive bonds [1].


Ultrasonic Attenuation Of Water-Infiltrated Thermal Barrier Coatings, Joachim Bamberg, Heinz Schmitt Jan 1993

Ultrasonic Attenuation Of Water-Infiltrated Thermal Barrier Coatings, Joachim Bamberg, Heinz Schmitt

Review of Progress in Quantitative Nondestructive Evaluation

For advanced aircraft gas-turbine engines greater efficiencies and higher thrust are demanded. One possibility to achieve this is to increase the gas temperature at the turbine-section. Then thermal barrier coatings are necessary to protect the metallic structures.


Thermal Coating Characterization Using Thermoelasticity, Christopher S. Welch, Michael J. Zickel Jan 1993

Thermal Coating Characterization Using Thermoelasticity, Christopher S. Welch, Michael J. Zickel

Review of Progress in Quantitative Nondestructive Evaluation

Synchronous demodulation techniques have been used for some time to measure thermal radiation produced by the small temperature changes associated with elastic stress in materials, the thermoelastic effect[l]. As reviewed in [2], these measurements have been employed primarily for inferring stress distributions in materials from the associated temperature distributions. Images of stress distribution have been made most often by assembling a large number of individual synchronous component measurements using specialized equipment [3]. Other investigators [4,5] have used subtraction of stroboscopic samples to build up similar images. Recently, techniques using full-field synchronous demodulation [6,7] have been reported using ...


Fast Photothermal Inspection Of Plasma-Sprayed Coatings Of Primary Circulation Seal Rings Of A Nuclear Reactor. Part Two: After The Trial Run, R. Lehtiniemi, J. Hartikainen, J. Rantala, J. Varis, M. Luukkala Jan 1993

Fast Photothermal Inspection Of Plasma-Sprayed Coatings Of Primary Circulation Seal Rings Of A Nuclear Reactor. Part Two: After The Trial Run, R. Lehtiniemi, J. Hartikainen, J. Rantala, J. Varis, M. Luukkala

Review of Progress in Quantitative Nondestructive Evaluation

In the 1991 QNDE conference [1] we described a photothermal inspection of the plasma-sprayed coatings of two seal rings used in the main pump of the primary circulation in the PWR-type nuclear reactor. The measurements concentrated on detecting the most critical flaw type, adhesion defects at the interface between the coating and the substrate. The samples were tested immediately after they were coated and lapped, and already then two thermal anomalies could be found.