EXTRADOS STRUCTURAL ELEMENT MADE FROM AN ALUMINIUM COPPER LITHIUM ALLOY

摘要

The invention relates to an extrados structural element made from an aluminum, copper and lithium alloy and a method for manufacturing same. In the method according to the invention, an alloy with composition (in wt %) 4.2 to 5.2 Cu, 0.9 to 1.2 Li, 0.1 to 0.3 Ag, 0.1 to 0.25 Mg, 0.08 to 0.18 Zr, 0.01 to 0.15 Ti, optionally up to 0.2 Zn, optionally up to 0.6 Mn, an Fe and Si content level less than or equal to 0.1% each, and other element with a content level less than or equal to 0.05% each and 0.15% in total, the aluminum is poured, homogenized, deformed hot and optionally cold, placed in a solution at a temperature of at least 515° C., pulled from 0.5 to 5% and annealed. The combination in particular of the magnesium, copper and manganese content with the temperature in solution can reach a very advantageous elasticity under compression limit. Thus, the products according to the invention having a thickness of at least 12 mm have an elasticity under compression limit in the longitudinal direction of at least 645 MPa and an elongation in the longitudinal direction of at least 7%.

主权项

1. A method for manufacturing an extruded, rolled and/or forged product made of an alloy containing aluminium, said method comprising
a) preparing a molten metal bath comprising 4.2 to 5.2% Cu by weight, 0.9 to 1.2% Li by weight, 0.1 to 0.3% Ag by weight, 0.1 to 0.25% Mg by weight, 0.08 to 0.18% Zr by weight, 0.01 to 0.15% Ti by weight, optionally up to 0.2% Zn by weight, optionally up to 0.6% Mn by weight, a Fe and Si content less than or equal to 0.1% by weight each, other elements with a content less than or equal to 0.05% by weight each and 0.15% by weight total, and the rest of aluminium; b) a rough shape is cast from said molten metal bath; c) said shape is homogenized by a heat treatment in which the temperature at mid-thickness of the rough shape reaches at least 510° C. for at least 10 hours, d) said rough shape is hot worked and optionally cold worked, then homogenized into an extruded, roll and/or forged product; e) said product is solution heat treated at a temperature of at least 515° C. and quenched; f) said product undergoes controlled stretching with a permanent set of 0.5 to 5%; g) said product is aged by heating to a temperature of 140 to 170° C. for 5 to 70 hours.