High temperature fatigue behavior of tungsten copper composites

Conference · Sun Oct 01 04:00:00 EDT 1989

OSTI ID:7025472

Verrilli, M J; Kim, Yongsuk; Gabb, T P

The high temperature fatigue behavior of a 9 vol percent, tungsten fiber reinforced copper matrix composite was investigated. Load-controlled isothermal fatigue experiments at 260 and 560 C and thermomechanical fatigue (TMF) experiments, both in phase and out of phase between 260 and 560 C, were performed. The stress-strain response displayed considerable inelasticity under all conditions. Also, strain ratcheting was observed during all the fatigue experiments. For the isothermal fatigue and in-phase TMF tests, the ratcheting was always in a tensile direction, continuing until failure. The ratcheting during the out-of-phase TMF test shifted from a tensile direction to a compressive direction. This behavior was thought to be associated with the observed bulging and the extensive cracking of the out-of-phase specimen. For all cases, the fatigue lives were found to be controlled by damage to the copper matrix. Grain boundary cavitation was the dominant damage mechanism of the matrix. On a stress basis, TMF loading reduced lives substantially, relative to isothermal cycling. In-phase cycling resulted in the shortest lives, and isothermal fatigue at 260 C, the longest.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
• OSTI ID: 7025472
• Report Number(s): N-90-21138; NASA-TM--102404; E--5156; NAS--1.15:102404; CONF-8910240--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
COMPOSITE MATERIALS
COMPRESSIBILITY
COPPER
CRYSTAL STRUCTURE
ELEMENTS
FATIGUE
FIBERS
GRAIN BOUNDARIES
HIGH TEMPERATURE
MATERIALS
MATRIX MATERIALS
MECHANICAL PROPERTIES
METALS
MICROSTRUCTURE
STRESS ANALYSIS
THERMAL FATIGUE
THERMODYNAMICS
TRANSITION ELEMENTS
TUNGSTEN