ULTRASONIC NONDESTRUCTIVE EVALUATION OF ELASTIC-CONSTANTS AND FRACTIONAL RATIO OF AL2O3 FIBER OF ALUMINUM BASE COMPOSITES

The purpose of this study was to develop a non-destructive material ev aluation method of aluminum alloy base metal matrix composite (MMC) by ultrasonics. Five aluminum base MMC specimens in which the fractional ratios of fiber were changed from 0% to 31% were fabricated. The rela tionship between the acoustic properties, microstructural features and elastic constant were compared. The ultrasonic velocity method was, t hen, useful for nondestructive elastic constant measurement of composi te materials, since this method had the same measurement accuracy as t he conventional strain measurement method. Furthermore, the velocity a nd attenuation parameter are also related to the fractional ratio of f iber and these relations may be utilized for the ultrasonic non-destru ctive evaluation of fiber structure in MMC.