Abstract
The present study has been designed to detect and characterize micro voids due to the Kirkendall effect in the TiNi intermetallic compound. The ultrasonic technique with immersion type focused transducer was employed. Various types of specimens were made by changing the heat treatment condition and the load stress. The UT signals were compared with the results of micrographs by means of metallurgical microscope. The attenuation ratio and the correlation coefficient between 1stand 2nd bottom echo were adopted at this time. In the ultrasonic simulation, the attenuation ratio and the void size were linear relations while the void echo amplitude became lower rapidly decreasing in the size of void. It was verified that the ultrasonic immersion method presented here has been performed for evaluation of the Kirkendall voids quantitatively in the TiNi intermetallic compounds. In addition, it was shown to be able to evaluate the size of voids and the positions by using wavelet analysis.
