Low Cycle Fatigue Properties of Advanced Engine Materials 670336
Low-cycle fatigue is a term used to describe the thermal and/or mechanical loading conditions which cause premature failure of materials at less than 20,000 cycles. These cyclic stress conditions are prevalent during engine start-up or shut down and in severe flight maneuvers. From the design standpoint, it is important to assess and predict the behavior of compressor and turbine component materials under these severe conditions.
This paper presents the low cycle fatigue data on six candidate materials which were considered for an advanced engine. The materials were investigated simultaneously by pull-pull and by modified rotating beam fatigue testing techniques. Results indicate that the candidate materials can sustain appreciable cycling at stress levels beyond design limit before fracture occurs by the low cycle fatigue mechanism. Of the materials investigated, Udimet 630 exhibited the optimum low cycle fatigue resistance.