Anisotropy Detection in Small Area of Materials using Surface Acoustic Waves : Basic Research on Utilization of Ultrasonic Reflectivity Measurement for Estimating Elastic Anisotropy

• Published in: Transactions of the Japan Society of Mechanical Engineers Series A Vol. 61; no. 584; pp. 769 - 776
• Main Authors: Ihara, Ikuo, Aizawa, Tatsuhiko, Koguchi, Hideo, Kihara, Junji
• Format: Journal Article
• Language: Japanese
• Published: The Japan Society of Mechanical Engineers 1995
• Subjects: Anisotropy; Elasticity; Measurement; Nondestructive Inspection; Small Area; Surface Wave; Ultrasonic Inspection; Ultrasonic Reflectivity
• ISSN: 0387-5008; 1884-8338
• DOI: 10.1299/kikaia.61.769

An ultrasonic reflectivity measurement technique is applied to anisotropy detection within a small area of material. The ultrasonic reflectivity is microscopically measured using an ultrasonic microspectrometer with spherical-planar-pair lenses. The acoustic reflection coefficients of small area on a water-cubic (111) interface were measured for an incident wave at an angle θ to the normal and φ to some direction lying in the (111) surface. The reflection coefficients measured as a function of θ and φ were in good agreement with the theoretical calculation. This reveals that the microscopically measured reflection coefficient is reasonable and can be used as a promising detector of anisotropy in a small area. Furthermore, a mean reflection coefficient is defined for quantitative evaluation of elastic anisoropy in a small area of polycrystalline materials. It has been confirmed that, by performing numerical and experimental examinations with texture-controlled steels, the reflection coefficient measured in polycrystalline materials corresponds to the mean reflection coefficient.