Nondestructive Damage Characterization of Alumina Ceramics

Abstract

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 highvelocity 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.