Other

The United States of America As Represented by the Administrator of the

Advanced Composite Materials Corporation

Edgar A Starke, Jr

Linda B Blackburn

Roy Crooks

J Andrew Walker

Lillianne P Troeger

Paul W Niskanen

A method for producing new superplastic alloys by inducing in an alloy the formation of precipitates having a sufficient size and homogeneous distribution that a sufficiently refined grain structure to produce superplasticity is obtained after subsequent PSN processing. An age-hardenable alloy having at least one dispersoid phase is selected for processing. The alloy is solution heat-treated and cooled to form a supersaturated solid solution. The alloy is plastically deformed sufficiently to form a high-energy defect structure useful for the subsequent heterogeneous nucleation of precipitates. The alloy is then aged, preferably by a multi-stage low and high temperature process, and precipitates are formed at the defect sites. The alloy then is subjected to a PSN process comprising plastically deforming the alloy to provide sufficient strain energy in the alloy to ensure recrystallization, and statically recrystallizing the alloy. A grain structure exhibiting new, fine, equiaxed and uniform grains is produced in the alloy. An exemplary 6xxx alloy of the type capable of being produced by the present invention, and which is useful for aerospace, automotive and other applications, is disclosed and claimed. The process is also suitable for processing any age-hardenable aluminum or other alloy.

Method of producing superplastic alloys and superplastic alloys produced by the method

A reinforced aluminum matrix composite having improved toughness and ductility over known composites, without any sacrifice in strength or stiffness. In particular, the invention relates to a reinforced aluminum alloy consisting essentially of copper and magnesium as the principal alloying elements. The alloy may have other soluble alloying elements up to their solubility limits in the base alloy. The alloy may include a small percentage of insoluble metallic elements in amounts which do not adversely affect the sought after improvements in ductility and toughness. The reinforcement may be either a ceramic material, in the form of whiskers, particles, or chopped fibers, or a metal.

Reinforced aluminum matrix composite

At least about 0.1 percent by weight of indium is added as an essential component to an alloy which precipitates a T.sub.1 phase (Al.sub.2 CuLi). This addition enhances the nucleation of the precipitate T.sub.1 phase, producing a microstructure which provides excellent strength as indicated by Rockwell Hardness values and confirmed by standard tensile tests.

Aluminum alloy

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Charlottesville, VA, United States of America

Edgar A Starke, Jr