Fatigue crack propagation behaviour of a nickel based superalloy at elevated temperatures

摘要

The fatigue crack growth behaviour of a nickel based superalloy at elevated temperatures 550, 650 and 710 degrees C was studied. The direct current potential drop (DCPD) technique was used to measure the crack length during the test. It was found that the crack growth rates slightly increased with increasing temperatures, but the temperature effect on crack growth rates was less pronounced at higher Delta K ranges. At the same temperature the crack growth rates increased with increasing load ratios. The oxidation induced crack closure is considered to be a reason of the observed crack growth behaviour in this study.