The Microstructural Influence on Fatigue Crack Growth in Rene 88DT
EMSL Project ID
16097
Abstract
In order to reduce materials development time in superalloy applications, it is necessary to develop physically-based models to predict the alloy's properties. Fatigue is a life-limiting property for superalloys, including Rene 88DT, and it is necessary to understand the microstructural influences the govern fatigue crack growth and path determination. This will provide a basis for future physically-based models. This project specifically examines how microstructural features in Rene 88DT, including gamma prime precipitates, carbides, and grain orientation, influence the surface roughness characteristics of the fracture surface. We are also determining if there are any "weak-link" phases in the microstructure where fatigue cracks preferentially grow. A confocal microscope will potentially provide valuable results on the surface roughness and characteristics of fatigue fracture surfaces as a function of depth as the stress-state transitions from plane stress on the specimen surface to plane strain in the specimen interior. These results will be correlated to observations microstructural features that are pertinent to fatigue crack growth. We anticipate acknowledging EMSL in any resulting publications.
Project Details
Project type
Exploratory Research
Start Date
2005-10-04
End Date
2007-07-06
Status
Closed
Released Data Link
Team
Principal Investigator