3434 Damping Characters of Shape Memory Alloy by Ultrasonic Wave
Details
The ultrasonic attenuation of Ni-Ti shape memory alloys is investigated over kilohertz range. There are three kinds of wire shape specimens, which are heat-treated by 400, 450 and 500℃. The martensitic transformation temperatures are obtained using by dynamic mechanical analysis and differential scanning calorimeter. Ultrasonic wave is carried to the specimen and the vibration is translated to the voltage by the sensor. The voltage, which is induced by the wave, is measured both input side and output side on the specimen and then the attenuation is obtained by differentiated voltages. The attenuations are measured during heating and cooling. It was found that some of attenuations vary at the temperature on which the specimens transform from martensite to austenite or vice versa.
