Fabrication and mechanical behaviour of aluminum matrix composite materials

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:7047933

Lim, Taewon

Aluminum matrix composite materials containing SiC whisker and Saffil alumina short fiber are fabricated by the squeeze casting method. It is demonstrated that the direct squeeze casting infiltration method is suitable for discontinuously reinforced metal matrix composites (MMC's) whose volume fractions are in the range of 0.15-0.3; squeeze casting of compounds for the fabrication of discontinuous MMC's with less volume fractions (less than 0.1). Mechanical properties, such as Young's modulus and ultimate tensile strength, are improved up to 80 percent by the addition of reinforcement. Hardness is improved by the incorporation of reinforcement. Optimum aging conditions for MMC's are determined. The peak aging time decreases with increasing the aging temperature and decreasing the volume fraction of reinforcement. Predictions for the elastic moduli and tensile strength are proposed from the transformed laminate analogy, and combinations of modified rule of mixtures and shear lag theory. Wear resistance of the composite is improved. The major wear mechanism of discontinuous MMC's is strongly dependent upon the sliding speed. Weight loss increases linearly with the sliding distance. From fracture surface analyses at room and elevated temperatures, it is found that the failure mode is ductile at the microstructural level and it becomes more ductile as temperature increases. Based on the fracture surface observations and experimental data, the strength reduction at elevated temperatures is due to overaging and softening of the matrix alloy. Failure mechanisms of the as-fabricated composites are summarized.

• Research Organization: State Univ. of New York, Buffalo, NY (United States)
• OSTI ID: 7047933
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
360603 -- Materials-- Properties
AGING
ALLOYS
ALUMINIUM ALLOYS
CARBIDES
CARBON COMPOUNDS
CASTING
COMPACTING
COMPOSITE MATERIALS
CRYSTAL STRUCTURE
CRYSTALS
DUCTILITY
ELASTICITY
FABRICATION
FAILURE MODE ANALYSIS
FIBERS
FRACTURE PROPERTIES
HARDNESS
MATERIALS
MATRIX MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
MONOCRYSTALS
REINFORCED MATERIALS
SILICON CARBIDES
SILICON COMPOUNDS
SYSTEM FAILURE ANALYSIS
SYSTEMS ANALYSIS
TEMPERATURE DEPENDENCE
TENSILE PROPERTIES
ULTIMATE STRENGTH
WEAR RESISTANCE
WHISKERS
YOUNG MODULUS