Abstract: A method for producing a metal matrix composite having improved properties includes the step of forming a sintered ceramic preform including a network of uniformly distributed ceramic particles having a particle size of 1 micron or less and being bonded together at their points of contact by sintering. After sintering to form a preform, the preform is placed in a mold and infiltrated with molten metal. The molten metal is then solidified to form a shaped body. This shaped body is then subjected to sufficient strain to eliminate at least 50% and preferably 80% of the bonds in the network. The shaped body is then subjected to a metal forming step such as wrought or semisolid forming.

Abstract: A light-weight metal matrix composite includes a bimodal distribution of ceramic particles which are uniformly distributed within a metal or alloy matrix. The bimodal distribution includes a first component of ceramic particles having an average particle size of less than 1 micron and a second component of ceramic particles having an average particle size of about 5 to 15 microns. The metal matrix composite includes from about 15 to 30% by weight of the first component and from about 2.5 to about 10% by weight of the second component. At least 80% of the particles in the first component are uniformly distributed so that the particle spacing does not exceed 3 times the diameter of the largest cross sectional dimension of the particles in the first component and at least 80% of the ceramic particles in the second component are uniformly distributed so that the inner particle spacing does not exceed 3 times the diameter of the largest cross sectional dimension of the particles in the second component.

Abstract: Metal-matrix composites and methods for producing these composites are provided. The manufacturing methods include providing a ceramic preform having a uniform distribution of ceramic particles sintered to one another. The particles include an average particle size of no greater than about 3 microns, and at least one half of the volume of the preform is occupied by porosity. The preform is then disposed into a mold and contacted by molten metal. The molten metal is then forced into the pores of the preform and permitted to solidify to form a solid metal-matrix composite. This composite is machinable with a high-speed steel (HSS) bit for greater than about 1 minute without excessive wear occurring to the bit. This invention preferably employs metal-matrixes including Al, Li, Be, Pb, He, Au, Sn, Mg, Ti, Cu, and Zn. Preferred ceramics include oxides, borides, nitrides, carbides, carbon, or a mixture thereof. Inert gas pressures of less than about 3,000 psi can be used to easily infiltrate the preforms.