Process for manufacturing clad aluminium-lithium alloys

Claim 1

A method for effecting a substantially uniform adhesion of substantially all of the contacting surfaces of a lithium-containing core alloy with a metallic liner material, characterised in that (a) opposed surfaces of the core alloy and the liner material are prepared by removing substantially all oxide materials therefrom; (b) the prepared surfaces are contacted in order to form a composite and the leading edges of each of the prepared surfaces are tacked together; (c) the composite is roll-bonded from the leading edges, in order to obtain substantially uniform adhesion along the contacting surfaces while causing at most a 2% reduction of the core alloy, at a temperature of up to about 230°C (450°F); and (d) the roll-bonded composite is heated to form a metallurgical bond between the core alloy and the liner material along substantially all of the contacting surfaces.

Claim 2

A method for effecting a substantially uniform adhesion of substantially all of the contacting surfaces of a lithium-containing core alloy with a metallic liner material, characterised in that (a) opposed surfaces of the core alloy and the liner material are prepared by removing substantially all oxide materials therefrom; (b) the prepared surfaces are contacted in order to form a composite and the leading edges of each of the prepared surfaces are tacked together; (c) the composite is roll-bonded from the leading edges, in order to obtain substantially uniform adhesion along the contacting surfaces while causing at most a 2% reduction of the core alloy, at a temperature of up to about 230°C (450°F); and (d) the roll-bonded composite is heated to form a metallurgical bond between the core alloy and the liner material along substantially all of the contacting surfaces.

Claim 5

A method in accordance with any of claims 1 to 3, in which step (c) is achieved by a plurality of successive rolling passes beginning with a sufficient number of passes at a total composite reduction of less than about 2% to secure at least a portion of the liner material to the core alloy.

Claim 6

A method in accordance with any preceding claim, in which the reduction of the core alloy in step (c) is at most about 1.5%.

Claim 7

A method in accordance with any preceding claim, in which step (d) is done at a temperature in the range from 315° to 650°C (600° to 1200°F) for at least 1 hour per 2.5 cm (1 hour per inch) of composite thickness.

Claim 10

A method in accordance with any preceding claim, in which the composite is hot-rolled subsequent to step (d) at a temperature in the range from 315° to 650°C (600° to 1200°F).

Claim 12

A method for cladding a lithium-containing aluminium core alloy with a metallic liner material at least about 0.5 mm (0.02 inch) thick to form a composite of which the liner material comprises 1.5% to 15% per side of the thickness thereof, characterised in that: (a) opposed surfaces of the core alloy and the liner material are prepared by removing therefrom substantially all oxide materials; (b) the prepared surfaces are contacted to form a composite and the leading edges of each of the prepared surfaces are tacked together; (c) the composite is roll-bonded from the leading edges to obtain substantially uniform adhesion along the contacting surfaces while causing at most a 15% reduction of the core alloy, at a temperature of up to about 220°C (425°F); and (d) the roll-bonded composite is heated to a temperature in the range from 425° to 600°C (800° to 1100°F) for at least about 3 hours per 2.5 cm (3 hours per inch) of composite thickness to form a metallurgical bond between the core alloy and the liner material along substantially all of the contacting surfaces.

Claim 13

A method for cladding a lithium-containing aluminium core alloy with a metallic liner material at least about 0.5 mm (0.02 inch) thick to form a composite of which the liner material comprises 1.5% to 15% per side of the thickness thereof, characterised in that: (a) opposed surfaces of the core alloy and the liner material are prepared by removing therefrom substantially all oxide materials; (b) the prepared surfaces are contacted to form a composite and the leading edges of each of the prepared surfaces are tacked together; (c) the composite is roll-bonded from the leading edges to obtain substantially uniform adhesion along the contacting surfaces while causing at most a 15% reduction of the core alloy, at a temperature of up to about 220°C (425°F); and (d) the roll-bonded composite is heated to a temperature in the range from 425° to 600°C (800° to 1100°F) for at least about 3 hours per 2.5 cm (3 hours per inch) of composite thickness to form a metallurgical bond between the core alloy and the liner material along substantially all of the contacting surfaces.