A creep cavity growth model for creep-fatigue life prediction of a unidirectional W/Cu composite

Conference · Fri May 01 04:00:00 EDT 1992

OSTI ID:7081167

Kim, Youngsuk; Verrilli, M J; Halford, G R

A microstructural model was developed to predict creep-fatigue life in a (0)[sub 4], 9 volume percent tungsten fiber-reinforced copper matrix composite at the temperature of 833 K. The mechanism of failure of the composite is assumed to be governed by the growth of quasi-equilibrium cavities in the copper matrix of the composite, based on the microscopically observed failure mechanisms. The methodology uses a cavity growth model developed for prediction of creep fracture. Instantaneous values of strain rate and stress in the copper matrix during fatigue cycles were calculated and incorporated in the model to predict cyclic life. The stress in the copper matrix was determined by use of a simple two-bar model for the fiber and matrix during cyclic loading. The model successfully predicted the composite creep-fatigue life under tension-tension cyclic loading through the use of this instantaneous matrix stress level. Inclusion of additional mechanisms such as cavity nucleation, grain boundary sliding, and the effect of fibers on matrix-stress level would result in more generalized predictions of creep-fatigue life.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
• OSTI ID: 7081167
• Report Number(s): N-93-10967; NASA-TM--105780; E--7207; NAS--1.15:105780; CONF-9205286--; CNN: RTOP 510-01-50
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
CAVITIES
COPPER
CREEP
CRYSTAL STRUCTURE
ELEMENTS
FATIGUE
FIBERS
FRACTURING
GRAIN BOUNDARIES
MATERIALS
MATHEMATICAL MODELS
MATRIX MATERIALS
MECHANICAL PROPERTIES
METALS
MICROSTRUCTURE
NUCLEATION
STRAIN RATE
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
THERMAL FATIGUE
TRANSITION ELEMENTS
TUNGSTEN