@article{oai:sucra.repo.nii.ac.jp:00012605,
 author = {加藤, 寛},
 issue = {4},
 journal = {NDT & E International},
 month = {},
 note = {http://www.sciencedirect.com/science/journal/09638695 | http://www.sciencedirect.com/science/journal/09638695, The present work is concerned with nondestructive evaluation of the thickness of the remelted zone formed on aluminum alloy castings by using ultrasonic backscattered waves. Remelted zones with different thicknesses were formed on the surface of an AI-Cu-Si alloy casting plate, and backscattered waves were measured at various positions on the plate by immersion method with different distances of the water path to obtain an optimum focal depth in the specimen. When the ultrasonic wave was focused on the boundary between the remelted zone and the matrix, the amplitude ratio of the backscattered wave from the matrix to that from the remelted zone reached a maximum. The longitudinal wave velocity and the density were measured with test pieces containing remelted zones to obtain acoustic impedances of the remelted zone and the matrix. The
reflectivity at the boundary calculated from the acoustic impedances was less than 1.5% (-37dB)., text, application/pdf},
 pages = {221--225},
 title = {Optimization of ultrasonic measurement of remelted zone thickness using backscattered waves},
 volume = {35},
 year = {2002},
 yomi = {カトウ, ヒロシ}
}