초록 ▼

This invention relates to the extrusion of aluminium-lithium alloys, desirably in the form of relatively thin sections, which are particularly suitable for aerospace applications. The invention provides a method of extruding a lithium-containing aluminium alloy containing at least 0.1% by weight of

This invention relates to the extrusion of aluminium-lithium alloys, desirably in the form of relatively thin sections, which are particularly suitable for aerospace applications. The invention provides a method of extruding a lithium-containing aluminium alloy containing at least 0.1% by weight of copper, which method comprises: a) providing a billet of the alloy in an homogenised condition at a temperature suitable for extrusion, wherein the alloy contains at least 1.5% by weight of lithium, b) extruding the billet at a temperature and at an extrusion rate such that essentially all of the components thereof are in solid solution as the extrudate leaves the extrusion die, and c) cooling the extrudate at a rate sufficient to avoid substantially any precipitation of the components thereof taking place. Corrosion of the extruded sections after quenching and after ageing can be substantially reduced by means of the present invention.

대표청구항 ▼

[ I claim:] [1.] A method of extruding a lithium-containing aluminum alloy having the composition in weight percent:______________________________________ lithium 1.7 to 2.8 magnesium 0 to 1.9 copper 1.0 to 3.0 manganese 0 to 0.9 zirconium 0 to 0.25 at least one other 0 to 0.5 grain-controlling elem

[ I claim:] [1.] A method of extruding a lithium-containing aluminum alloy having the composition in weight percent:______________________________________ lithium 1.7 to 2.8 magnesium 0 to 1.9 copper 1.0 to 3.0 manganese 0 to 0.9 zirconium 0 to 0.25 at least one other 0 to 0.5 grain-controlling element nickel 0 to 0.5 zinc 0 to 0.5 aluminum balance (except for incidental impurities) ______________________________________wherein the other grain-controlling elements are selected from the group consisting of hafnium, niobium, scandium, cerium, chromium, titanium and vanadium, and wherein at least one of (i) manganese, (ii) zirconium, and (iii) one of the said other grain controlling elements is present, which method comprises:(a) providing a billet of the alloy in an homogenized condition at a temperature suitable for extrusion,(b) extruding the billet at a temperature and at an extrusion rate such that essentially all of the components thereof are in solid solution as the extruded billet leaves the extrusion die, and(c) quenching the extruded billet with water down from its extrusion temperature to below its solvus temperature in the absence of any intermediate step at a rate sufficient to avoid substantially any precipitation of the components thereof taking place, thereby obtaining an extruded and quenched billet which is substantially corrosion-free.