分散性弾性波の順解析による高温環境劣化割れのメカニズム

第1報: 耐熱AEセンサーの試作とレーザ超音波による高温音響特性の非破壊評価

抄録

In order to study the mechanism of environmental assisted cracking of metallic materials at high temperatures, a new heat resistant acoustic emission (AE) sensor was developed and utilized to measure the acoustic and mechanical properties of the SUS 304 stainless steel at temperatures lower than 600°C. The capacitive type AE sensor with an amorphous alumina film deposited by an electron-cyclotron resonance laser PVD method was found to measure the out-plane displacement in the broad frequency band, but show a slight response delay due to the relatively large sensor area. Both the phase velocity and wave attenuation of the SUS 304 steel at elevated temperatures were successfully measured utilizing the Q-switched YAG laser and the developed AE sensor. A new signal processing for the source inversion of the dissipative elastic waves, including the wave attenuation, the time retardation function of the sensor and the analytical transfer function of the hot medium, was proposed.