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Title: High-energy - high-rate power processing of aluminum-silicon carbide metal-matrix composites

Thesis/Dissertation ·
OSTI ID:7202451

Discontinuous, silicon-carbide-reinforced, aluminum metal-matrix composite metals were made by consolidating powder constituents using a novel high-energy - high-rate process that employs a fast-rising high-current pulse. The powder mixtures were contained in an insulated die, under pressure, and were rapidly densified during the discharge from a homopolar generator, in a processing time of about one second. Several types of rapidly solidified Al-based powders, X7091, CW67, and 7064, were reinforced with different types and volume fractions of discontinuous SiC. The consolidate materials were evaluated using optical and analytical electron microscopy and Auger spectroscopy to determine the microstructure and to identify the phases evolved. Processing/structure/property interrelationships were established. Energy inputs of 400 kJ/kg to 2500 kJ/kg at applied pressures of 105 to 315 MPa resulted in consolidated forms, having a homogeneous distribution of the SiC particles within the composite. Densities of 95% to 99% of theoretical were obtained with local interparticle melting contributing to densification at the highest energy levels. A direct correlation exists between the density, hardness, and fracture tensile strength, and the specific input energy, indicating that metallurgical bonding and densification scaled with input energy.

Research Organization:
Texas Univ., Austin (USA)
OSTI ID:
7202451
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English