Interface engineering in alumina fiber/glass composites

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:7198117

Venkatesh, R

The goal of the present study is the development of tough alumina fiber/glass composites. Alumina and glass form a chemical bond and hence the resulting composite is brittle. SnO2 has been shown to have no solubility in alumina and very little diffusion in glass. A weakly bonded SnO2 interphase would aid in crack deflection, fiber debonding, and/or fiber pullout in alumina/SnO2/glass composites. The proposed study modifies the interface of alumina fiber/glass composites by incorporating a layer of SnO2, and characterizes the physical and mechanical properties of the resultant composites. Thermal stresses evaluated from a three-element cylindrical model showed radial tensile stress in both PRD-166/SnO2/glass and single crystal alumina Saphikon/SnO2/glass matrix composites. Even though there was weak mechanical bonding and tensile radial thermal stress at the PRD-166/SnO2 interface, the fibers could not be pushed out during a nanoindentation test. This was attributed to fiber roughness causing a compressive clamping stress at the PRD-166/SnO2 interface. PRD-166/glass matrix composites failed in a brittle manner whereas PRD-166/SnO2/glass matrix composites exhibited nonplanar failure with crack deflection and fiber bridging as the major toughening mechanisms. Saphikon/SnO2/glass matrix composites failed in a tough manner with extensive fiber pullout. This difference in the mode of failure was due to a relatively smooth Saphikon fiber. Fracture toughness of PRD-166/glass and PRD-166/SnO2/glass matrix composites measured with a chevron notch showed that the toughness of PRD-166/SnO2/glass matrix composite was higher than that of PRD-166/glass matrix composites because of crack deflection, fiber bridging, partial fiber debonding, and some fiber pullout. A judicious interplay of roughness induced radial stress and thermal stress distribution can be used to make a tough CMC.

• Research Organization: New Mexico Inst. of Mining and Technology, Socorro, NM (United States)
• OSTI ID: 7198117
• Resource Relation: Other Information: Ph.D. Thesis
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
BONDING
INTERFACES
GLASS
MATRIX MATERIALS
FRACTURE PROPERTIES
CRACK PROPAGATION
THERMAL STRESSES
TIN OXIDES
ALUMINIUM COMPOUNDS
CHALCOGENIDES
FABRICATION
JOINING
MATERIALS
MECHANICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
STRESSES
TIN COMPOUNDS
360603* - Materials- Properties
360601 - Other Materials- Preparation & Manufacture