Metal matrix compositions and method of manufacture thereof

Abstract

An improved metal matrix composite which, in a preferred embodiment disclosed herein, utilizes boron carbide as the ceramic additive to a base material metal. The metal matrix composite of the present invention begins with the preparation of the boron carbide powder by particle size selection in a jet mill. The resulting powder and metal powder are then mixed by blending of powder of all the various elements such as by means of a conventional blender to uniformly mix powdered substances and avoid stratification and settling. After the particles have been sufficiently mixed, they are degassed and then placed into a die and then into a cylindrical container where the particulates are subjected to extremely high pressures transforming the elements into a solid ingot. It is from these ingots that the extrusion tubes or other articles of manufacture may then be made. The resulting advanced metal matrix composite is in the boron carbide embodiment of the invention, 60% lighter, 30% stronger, 40-45% stiffer and 50% higher in fatigue strength than any of the top of the line 7000 series aluminum alloy materials. In the preferred embodiment disclosed herein the base material metal is preferably an aluminum alloy or titanium alloy provided in powder form and preferably being approximately 97% pure with the balance of the material comprising various trace metals such as chromium, copper, iron, magnesium, silicon, titanium and zinc. The boron carbide powder is preferably 99.5% pure boron carbide having a particulate size in the range of 2-19 microns with a mean or average size of approximately 8.4 microns. In one typical embodiment of the invention, the metal base material was selected from an aluminum alloy 6061T-6 to which was added approximately 12% by weight, the aforementioned boron carbide powder to which was added silicon in an amount of 0.1-0.4%, iron in the amount of 0.05-0.4% and aluminum in an amount of 0.05-0.4%. The underlying boron carbide material was approximately 77% boron content and 22% carbon content.

Dependencies are inferred from the claim text.