초록 ▼

Low-density composites are produced consisting chiefly of boron carbide and aluminum, or aluminum alloy, and minor amounts of ceramic material. The method allows control of the rate of reaction between boron carbide and metal so that the final components of the composite, and hence the mechanical pr

Low-density composites are produced consisting chiefly of boron carbide and aluminum, or aluminum alloy, and minor amounts of ceramic material. The method allows control of the rate of reaction between boron carbide and metal so that the final components of the composite, and hence the mechanical properties, are controlled. The invention includes modification of the carbon content of the boron carbide composition, dispersion of boron carbide and formation of a compact, infiltration of the compact by aluminum or aluminum alloy, and heat treatments. The invention produces low-density boron carbide-aluminum composites with a homogeneous microstructure possessing desired mechanical properties.

대표청구항 ▼

A method of making a boron carbidealuminum composite, comprising: heating a particulate boron carbide in the presence of free carbon to 1800°-2250°C. wherein the resulting boron carbide exhibits a substantially reduced reaction rate with aluminum; and reacting said boron carbide with aluminum, where

A method of making a boron carbidealuminum composite, comprising: heating a particulate boron carbide in the presence of free carbon to 1800°-2250°C. wherein the resulting boron carbide exhibits a substantially reduced reaction rate with aluminum; and reacting said boron carbide with aluminum, wherein a boron carbide-aluminum composite is formed having a microstructure including principally boron carbide and aluminum metal homogeneously distributed throughout said composite. A method of making a boron carbide-aluminum composite of selected ceramic and metal content and microstructure, having high fracture toughness, fracture strength and Young\s modulus, and low density, comprising; dispersing a particulate boron carbide of less than 10 micrometers average particle size in water at a pH selected to maximize electrostatic repelling forces on boron carbide particle surfaces; consolidating said boron carbide into a porous compact; sintering said compact, whereby an open porous structure is retained; infiltrating said compact with aluminum; and heat treating said compact, whereby a voidless composite is formed having a plurality of microstructure phases.