熱衝撃を受けたセラミックスの超音波による特性評価

概要

論文の詳細を見る
Ultrasonic measurements at high frequency are expected as nondestructive inspection methods for ceramics, composites and functionally gradient materials. Ultrasonic testing and ultrasonic microscopy are two main nondestructive measurement methods being used in industrial areas; the former is suitable for detecting fine flaws in opaque materials and the latter is available for characterization of the materials. In this report, these two methods are used to evaluate ceramics that received heat shock by laser irradiation on the surface. Inside cracks with openings on the surface were measured by ultrasonic testing. Crack shapes were plotted by digitizing and detecting the echoes from the crack surface. It is observed that the cracks, which are perpendicular to the surface, change their direction to horizontal inside the materials and then stop their advances. Surface wave velocity was measured by an ultrasonic microscope. It is found that the velocity at damaged areas is lower than that at less-damaged areas. Ultrasonic microscopy can also detect fine cracks on or near the surface.
一般社団法人日本機械学会の論文
1991-12-25