Influence of microstructure on mechanical properties in cemented tungsten carbides

Thesis/Dissertation · Sun Jan 01 00:00:00 EST 1984

OSTI ID:5495491

Cutler, R A

A wide variety of tungsten carbide based composites was investigated to determine how microstructure affects the mechanical performance of these materials, with particular emphasis placed on fracture toughness. These ceramic-metal composites contain cobalt and/or nickel binders as the ductile metal phase. The metallic phase is highly constrained in tension by the lower thermal contraction of the carbide phase during cooling from liquid phase sintering temperatures. The carbide grains are correspondingly left in compression. A simple model is used to show how these internal residual stresses cause the fracture toughness to increase as the fracture mode of tungsten carbide grains change from intergranular to transgranular. Additionally, macroscopic residual stresses are often found in cemented carbides due to rapid binder solidification, binder migration, and mechanical treatment (grinding, erosion and impact) of the surface after sintering or hot isostatic pressing. Experimental results show that macroscopic compressive stresses near the surface of the composite increase the apparent toughness.

• Research Organization: Utah Univ., Salt Lake City (USA)
• OSTI ID: 5495491
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERMETS
FRACTURE PROPERTIES
RESIDUAL STRESSES
COMPOSITE MATERIALS
TUNGSTEN CARBIDES
BINDERS
MICROSTRUCTURE
CARBIDES
CARBON COMPOUNDS
CRYSTAL STRUCTURE
MATERIALS
MECHANICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
STRESSES
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
360203* - Ceramics
Cermets
& Refractories- Mechanical Properties
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360303 - Composite Materials- Mechanical Properties- (-1987)