Micromechanisms of creep-fatigue crack growth in a silicide-matrix composite with SiC particles

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1993.tb08317.x· OSTI ID:5992223

Ramamurty, U; Kim, A S; Suresh, S ^[1]; Petrovic, J J ^[2]

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1. Brown Univ., Providence, RI (United States)
2. Los Alamos National Lab., NM (United States)

An experimental study has been conducted to examine the cyclic fatigue crack growth characteristics in 1,200 C air of a MoSi[sub 2]-50 mol% WSi[sub 2] alloy in the unreinforced condition and with 30 vol% SiC particles. For comparison purposes, crack growth experiments under sustained loads were also carried out in the silicide-matrix composite. Particular attention is devoted to developing an understanding of the micromechanism of subcritical crack growth by recourse to optical and electron microscopy, including transmission electron microscopy of crack-tip damage. The results indicate that enhanced viscous flow of glass films along interfaces and grain boundaries imparts pronounced levels of subcritical crack growth in the composite material; the composite exhibits a higher fatigue fracture threshold and a more extended range of stable fracture than the unreinforced alloy. The effects of glass phase in influencing fatigue crack growth in the silicide-based material are compared to the influence of in situ-formed and preexisting glass films on high-temperature cyclic fatigue crack growth in ceramics and ceramic composites. The paper concludes with a comparison of present results with the high-temperature damage tolerance of a variety of intermetallic alloys and ceramic materials.

• DOE Contract Number: FG02-84ER45167
• OSTI ID: 5992223
• Journal Information: Journal of the American Ceramic Society; (United States), Vol. 76:8; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
CRACK PROPAGATION
MOLYBDENUM SILICIDES
SILICON CARBIDES
TUNGSTEN SILICIDES
CREEP
FATIGUE
FRACTURE MECHANICS
GRAIN BOUNDARIES
INTERFACES
MATRIX MATERIALS
OPTICAL MICROSCOPY
REINFORCED MATERIALS
TEMPERATURE RANGE 1000-4000 K
TRANSMISSION ELECTRON MICROSCOPY
WHISKERS
CARBIDES
CARBON COMPOUNDS
CRYSTALS
ELECTRON MICROSCOPY
MATERIALS
MECHANICAL PROPERTIES
MECHANICS
MICROSCOPY
MICROSTRUCTURE
MOLYBDENUM COMPOUNDS
MONOCRYSTALS
REFRACTORY METAL COMPOUNDS
SILICIDES
SILICON COMPOUNDS
TEMPERATURE RANGE
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
360603* - Materials- Properties