An ultrasonic fatigue testing machine for high temperature fatigue tests was developed. This machine can be operated up to 1000℃. In carrying out high temperature ultrasonic fatigue testing, careful attention must be paid to temperature effects on elastic modulus, horn design and so on. In this study, all of these problems were solved and validity of the developed machine was confirmed. More specifically, ultrasonic fatigue tests were conducted on heat resistance steel for boiler at 650℃ and on Ni-base single crystal superalloy for turbine blade at 1000℃. As the result, the ultrasonic fatigue testing show good agreements with conventional fatigue testing.
