Development of ultrasonic techniques with buffer rod in molten aluminum

The development of ultrasonic techniques for imaging and measurements in molten aluminum (Al) using clad buffer rods operated at 10 MHz is presented. The ultrasonic image of a character "N", engraved on a stainless steel plate immersed in molten Al, has been observed at 780/spl deg/C using the focused probe. Inclusion detection experiments have been conducted in reflection configurations involving pitch-catch and pulse-echo modes. The backscattered ultrasonic signals from the silicon carbide particles with an averaged diameter of 50 /spl mu/m suspended in molten Al are successfully detected due to the high signal-to-noise ratio of the clad buffer rods.