Processing of a mullite-matrix, molybdenum disilicide reinforced composite. Master's thesis

Technical Report · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5733788

Brynsvold, R

A mullite matrix reinforced with molybdenum disilicide particles was investigated as a potential high temperature composite material. Mullite is well known for its high temperature strength, creep resistance, corrosion resistance and ability to withstand oxidizing environments. MoSi2 has the potential to be a good reinforcement because: it forms a protective silica layer during oxidation, undergoes a brittle to ductile transformation at 900-1000C which would increase high temperature composite toughness, and is thermodynamically stable with mullite. Samples containing 2.5 to 20 vol% MoSi2 were processed using both hot pressing and pressureless sintering techniques. Low temperature mechanical testing was performed both in the as sintered state and after oxidation at 1400 C for 96 hours. Densities of greater than 93% of theoretical were attained for composites containing up to 20 vol% MoSi2 via pressureless sintering. K(sub Ic) and strength values of the as-sintered composite were up to two times that of monolithic mullite. After oxidation at 1400 C for 96 hours, strength improved by 1.5 times over the as-sintered s*trength, and fracture toughness improved by 2.5 times over the as-sintered toughness indicating that the composite is self-healing during oxidation.

• Research Organization: Washington Univ., Seattle, WA (United States). Dept. of Materials Science and Engineering
• OSTI ID: 5733788
• Report Number(s): AD-A-244985/8/XAB
• Resource Relation: Other Information: Thesis (M.S.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
FABRICATION
MECHANICAL PROPERTIES
OXIDATION
MOLYBDENUM SILICIDES
MULLITE
BRITTLENESS
COLLOIDS
CORROSION RESISTANCE
CREEP
DUCTILITY
FRACTURE PROPERTIES
HOT PRESSING
LAYERS
MATRIX MATERIALS
MOLYBDENUM ALLOYS
PARTICLES
PHASE TRANSFORMATIONS
PROCESSING
REINFORCED MATERIALS
SILICIDES
SILICON OXIDES
SINTERING
ALLOYS
CHALCOGENIDES
CHEMICAL REACTIONS
DISPERSIONS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
MATERIALS WORKING
MINERALS
MOLYBDENUM COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PRESSING
REFRACTORY METAL COMPOUNDS
SILICON COMPOUNDS
TENSILE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
360601* - Other Materials- Preparation & Manufacture
360603 - Materials- Properties
360604 - Materials- Corrosion
Erosion
& Degradation