High-temperature ultrasonic fatigue testing of single-crystal superalloys

摘要

A high-temperature ultrasonic fatigue testing system was developed to evaluate the gigacycle fatigue properties of single-crystal superalloys used in aircraft engine turbine blades. In this development, a commercial ultrasonic fatigue testing machine was considerably modified to achieve high-temperature fatigue testing. The testing system was first applied to a heat-resistant steel at 650 ℃ to check its accuracy, and next to SC superalloy samples at 1000 ℃. As a result, the ultrasonic fatigue testing showed good agreement with the conventional fatigue testing, demonstrating the high accuracy of the developed system. In these results, the SC superalloys showed no fatigue limit, indicating gigacycle fatigue tests to be necessary.