An Analysis of the Low Cycle Fatigue Behavior of the Superalloy Rene 95by Strainrange Partitioning.

摘要

This report describes the results of a research program to examine the applicability of the Strainrange Partitioning (SRP) method for predicting high temperature low cycle fatigue (LCF) crack initiation. Strain controlled LCF tests were performed at 922K (1200 F) on Rene 95, a high strength nickel-base superalloy, and SRP was used to correlate the data, as well as, to predict the number of LCF cycles to failure for a series of validation tests. The data indicate that for Rene 95 compressive dwell cycles are more damaging than tensile dwell cycles, and the LCF behavior depends largely on the time in tension per cycle and on the value of the maximum tensile stress. SRP was unable to satisfactorily predict the cyclic life for several types of LCF tests because the model is not capable of accounting for particular aspects of the alloys cyclic behavior, particularly the development of mean stresses. (Author)