Development of an ultrasonic fatigue testing machine at high temperature up to 1000℃

研制了一种用于高温疲劳试验的超声疲劳试验机。这台机器可以在1000℃下工作。在进行高温超声疲劳试验时，必须注意温度对弹性模量的影响、变幅杆的设计等问题，本研究解决了这些问题，证实了所研制的超声疲劳试验机的有效性。更具体地，在650℃下对锅炉用耐热钢和在1000℃下对涡轮机叶片用Ni基单晶高温合金进行超声疲劳试验。结果表明，超声疲劳试验与常规疲劳试验具有良好的一致性。

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.