Fatigue crack propagation in Ni-based superalloy single crystals under multiaxial cyclic loads
- Southwest Research Institute, San Antonio, TX (USA)
The effects of crystallographic orientation and stress state on the multiaxial fatigue behavior of single crystals of a Ni-based superalloy are examined. Using precracked CT specimens and notched tubular specimens subjected to combined tension/torsion cyclic loads, crack growth rates in modified Mar-M200 single crystals were determined at ambient temperature as functions of stress intensity range, the normal stress to shear stress ratio, and crystallographic orientations. Comparison of crack growth date at the same effective {Delta}K reveals that the crack growth rate increases with the applied normal stress to shear stress ratio. In all cases, subcritical cracking occurs along the (111) slip planes, and the fracture surfaces exhibit a cleavage-like appearance. The crack growth behavior is discussed in terms of anisotropic fracture mechanics, crack-tip slip morphology, and crack closure.
- OSTI ID:
- 5309113
- Report Number(s):
- CONF-840909--
- Journal Information:
- TMS (The Metallurgical Society) Paper Selection; (USA), Journal Name: TMS (The Metallurgical Society) Paper Selection; (USA) Vol. 56; ISSN 0197-1689; ISSN TMPSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CLEAVAGE
CLOSURES
CRACK PROPAGATION
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
FAILURES
FATIGUE
FRACTURE MECHANICS
FRACTURES
MECHANICAL PROPERTIES
MECHANICS
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
ORIENTATION
SLIP
STRESS INTENSITY FACTORS
STRESSES