Kirkendal void occurred

Telah dilakukan penelitian di Sekine Lab, YNU untuk void dengan ukuran sekitar 10 mikro meter yang muncul pada bahan clad tembaga-nikel. Proses pembuatan bahan uji dilakukan di Sumitomo Metal, Kansai area. (Sebagaimana dapat dilihat pada SEM fotograf).

The Cu/Ni clad specimens with a total thickness of 1»1,5 mm used for the tests have been produced by rolling and diffusion bonding process with various heat treatments; A (800 C/3min), B (1000 C/3min), C(1000 C/10min) and D (1000 C/60min). In the specimen A, no void is formed and in the other types of specimen, void formation and growth occur depending the condition of heat treatment.

Selection of the optimized distance (OD) on UT immersion method

Even the focusing distance of the transducer was decided by the manufacture. It is necessary to determine the optimized distance between the transducer and the specimen in order to obtain the good result of detection. For this purpose, the artificial defect was made on the Cu specimen such flatted bottom hole with the depth was ½ of thickness. The experiment has been done within range 14 – 31 mm. In this experiment, the echo height as representation of the OD was determined as shown in the figure. (The UT system installed for this study consists of ultrasonic pulser-receiver, oscilloscope digitizer, x-y scanner driver and 35 MHz focusing transducer with 5 mm diameter, Sekine Lab, YNU.)
Ada juga cara yang bisa digunakan sebagaimana tertulis pada buku training untuk ultrasoniknya ASNT, bagaimana menentukan focusing untuk probe spherical atau Cylindrical?