Orientation and temperature dependence of some mechanical properties of the single-crystal nickel-base superalloy Rene N4. II. Low cycle fatigue behavior

Journal Article · Sat Mar 01 04:00:00 EST 1986 · Metall. Trans., A; (United States)

DOI:https://doi.org/10.1007/BF02643956· OSTI ID:7225627

Gabb, T P; Gayda, J; Miner, R V

The low cycle fatigue (LCF) properties of a single-crystal nickel-base superalloy Rene N4, have been examined at 760 and 980 C in air. Specimens having crystallographic orientations near the 001, 011, -111, 023, -236, and -145 lines were tested in fully reversed, total-strain-controlled LCF tests at a frequency of 0.1 Hz. At 760 C, this alloy exhibited orientation dependent tension-compression anisotropies of yielding which continued to failure. Also at 760 C, orientations exhibiting predominately single slip exhibited serrated yielding for many cycles. At 980 C, orientation dependencies of yielding behavior were smaller. In spite of the tension-compression anisotropies, cyclic stress range-strain range behavior was not strongly orientation dependent for either test temperature. Fatigue life on a total strain range basis was highly orientation dependent at 760 and 980 C and was related chiefly to elastic modulus, low modulus orientations having longer lives. Stage I crack growth on 111 planes was dominant at 760 C, while Stage II crack growth occurred at 980 C. Crack initiation generally occurred at near-surface micropores, but occasionally at oxidation spikes in the 980 C tests. 13 references.

• Research Organization: NASA, Lewis Research Center, Cleveland, OH
• OSTI ID: 7225627
• Journal Information: Metall. Trans., A; (United States), Journal Name: Metall. Trans., A; (United States) Vol. 17A; ISSN MTTAB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CHROMIUM ALLOYS
COBALT ALLOYS
CRACK PROPAGATION
CRACKS
CRYSTALS
ENGINES
FATIGUE
GAS TURBINE ENGINES
HEAT ENGINES
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
INTERNAL COMBUSTION ENGINES
LATTICE PARAMETERS
MATERIALS
MECHANICAL PROPERTIES
MONOCRYSTALS
NICKEL ALLOYS
NICKEL BASE ALLOYS
TEMPERATURE DEPENDENCE