Nondestructive Damage Characterization of Alumina Ceramics

Report No. ARL-TR-4895
Authors: Raymond E. Brennan; James M. Sands; William H. Green; Jian H. Yu
Date/Pages: July 2009; 36 pages
Abstract: A qualitative evaluation of surface and bulk damage and a quantitative percent damage assessment were used to compare the integrity of several nondestructive characterization techniques. X-ray digital radiography and ultrasound C-scan imaging were compared for their ability to detect damage in aluminum-backed alumina test samples. Incremental damage was produced by two different methods, including high-mass, low-velocity drop tower testing for large crack and low mass generation, and high-velocity fragment-simulating projectile testing for hairline crack generation. Surface damage was analyzed by visual inspection as a baseline before utilizing digital radiography and C-scan imaging. While both nondestructive techniques were able to detect the full extent of surface damage, C-scan imaging was more effective at detecting internal damage in the alumina samples, finding a significant number of cracks that were not detected through digital radiography. A corresponding assessment of a quantitative damage percent revealed higher and more accurate values from the C-scan images as compared to the digital radiography images due to the increased detection of bulk damage.
Distribution: Approved for public release
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Last Update / Reviewed: July 1, 2009