位相検出型超音波顕微鏡による非鉄金属材料の微小領域における弾性定数測定

抄録

The acoustic microscope is well known for non-destructive testing equipment. Recently, it finds wide application to quantitative measurement of physical properties of specimens using the V(z) curve that is a special characteristic of acoustic microscope. In this study, the new method is described for the non-destructive measurement of elastic constants and poisson’s ratio of non-ferrous metals in a very small area using an amplitude and phase acoustic microscope.
According to the elastic theory, elastic constants and poisson’s ratio are calculated from the longitudinal and shear wave velocities of a specimen. Both wave velocities can be measured by the complex V(z) curve that involves the amplitude and phase of the reflected signal from the specimen surface.
Seven pure non-ferrous metal specimens are selected for this experiment. After complex V(z) curves are measured at 400 and 600 MHz, their inverses Fourier transforms are calculated. Longitudinal and shear wave velocities are calculated from their critical angles obtained from the inverse Fourier transform. Elastic constants and poisson’s ratio are calculated by both velocities and the density. The values of measured elastic constants and poisson’s ratio for each specimen are in good agreement with the value in the data-book.
According to this results, it is shown that this method is applicable to the measurement of elastic constants and poisson’s ratio of non-ferrous metals in a small area.