水素劣化材の破壊に伴うAE原波形特性

概要

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In order to examine the applicability of an acoustic emission source wave analysis to the detection and the evaluation of material degradtion, the acoustic emission genarated during fracture toughness test of a hydrogen attacked steel was investigated. AE signals were classified into two types according to their source wave characteristics. One was a signal due to microcracking at the non-metallic inclusions, and the other was a signal due to coalescence of the voids. AE activity of the hydrogen attacked specimen was lowered compared with that of the non-degraded specimen because the fracture of the hydrogen attacked steel was a intergranular fracture caused by coalescence of the micro bubbles on the grain surface and some inclusion had already debonded in the process of hydrogen attack. The formation of the micro bubbles caused the increase of the damping ratio of the AE signals in the higher frequency range and the reduction of the sound velocity.
一般社団法人日本機械学会の論文
1989-01-25