The Secretary of State for Defence in Her Britannic Majesty's Government

The Secretary of State for Defence in Her Brittanic Majesty's Government

Defence Research Agency

The Secretary of Defense in Her Britannic Majesty's Government of the

Christopher J Peel

Roger Moreton

Brian Evans

William S Miller

Samuel James Harris

Timothy Frederick Bryant

Alan J Shakesheff

Keith Dinsdale

Brian Noble

Stephen Mark Flitcroft

Stanley P Lynch

Simon Brian Dodd

A treatment process for a composite comprising a matrix of a precipitation hardenable aluminum alloy and a particulate or short fiber ceramic reinforcement. The process includes hot and/or cold working the composite, subjecting the composite to a controlled heating step in which the composite is raised from ambient temperature to a temperature of from 250 to 450.degree. C. at a rate of temperature increase less than 1000.degree. C. per hour, and subjecting the resulting heat treated composite to a solution treating step.

Method of treatment of metal matrix composites

Metal matrix composite

The stiffness of materials formed from aluminum alloy sheets laminated with layers of long aligned fibers embedded in a matrix of resin material is enhanced by reinforcing the aluminum alloy component with ceramic particles or whiskers. Use of stiff fibers such as carbon, aramid, alumina, silicon carbide or mixtures of these enables the stiffness of the fiber/resin component to be matched to that of the metal/ceramic component. This results in good fatigue crack growth resistance in the finished laminate, even for short crack lengths. In a preferred laminate, the metal/ceramic component is formed with a matrix of aluminum-lithium alloy. Such alloys are inherently stiffer than alloys without lithium, with the result that the increased stiffness obtained from ceramic reinforcement is enhanced stiff further.

Reinforced alloy laminates

Auxiliary heat treatment for aluminium-lithium alloys

Aluminum alloys

Aluminium alloys having compositions within the ranges (in wt %) 2 to 2.8 lithium--0.4 to 1 magnesium--1 to 1.5 copper--0 to 0.2 zirconium--0 to 0.5 manganese--0 to 0.5 nickel--0 to 0.5 chromium--balance aluminium. The alloys are precipitation hardenable and exhibit a range of properties, according to heat treatment, which make them suitable for engineering applications where light weight and high strength are required.

Aluminium alloys

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Christopher J Peel