Cegedur Societe De Transformation De L'aluminium Pechiney

Pechiney

Societe De Vente De L'aluminium Pechiney

Cegedur Societe De Transformation De L'aluminum Pechiney

Cegedur Societe De Transformation De L'aluminum Perchiney

Bruno Dubost

Philippe Meyer

Jean Marie Bouvaist

Jean-Marc Lang

Marc Audier

The invention concerns an Al alloy product containing lithium, with great specific mechanical strength and high tolerance to damage, particularly resistance to corrosion under stress in processed state (quenched-tempered), particularly in recrystallized state, and a process to obtain said product. The products according to the invention present a specific microstructure, with numerous rather coarse precipitates of intermetallic phases which are rich in Al, Cu, Li, Mg and optionally also Zn, of which the volume fraction is between 0.6 and 4%. A differential enthalpic analysis allows verification that the product has been processed according to the method which is claimed. This method consists of applying the following thermal treatments to the alloy:

A alloy product containing Li, resistance to corrosion under stress, and

The invention concerns a metal alloy with large lattice spacings (&gt;than 1 nm), and consisting essentially of, by weight: at least one element selected from a group A consisting of Al, Zn and Cu, total group A elements being 44-92%; at least one element selected from a group B consisting of Ag, Ga and Au, total group B elements being 0-46%, with % group A+group B=88-92%, and ##EQU1## a group C element which is Li in an amount of 7.2-12%; at least one element selected from a group D consisting of Mg, K, Na, and Ca, total group D elements being 0-12%, with % group C+% group D=8-12%, ##EQU2## and % group A+% group B+% group C+% group D=100%; said alloy additionally comprising elemental impurities in an amount of less than 1% each and less than 5% total, based on the total weight of the alloy.

Metal alloy with large lattice spacing

The invention relates to aluminum based alloys essentially containing Cu, Li and Mg, which have very high specific mechanical strength and can be used particularly to obtain heat treated articles of complex shapes. The analyses are as follows (as % by weight): Cu 2.4 to 3.5%, Li 1.9 to 2.7%; Mg from 0 to 0.8%; and up to: 0.20% Fe; 0.10% Si; 1% Mn; 0.30% Cr; 0.2% Zr; 0.1% Ti 0.02% Be preferably with the following limitation: 4.8.ltoreq.% Cu+% Li+% (Mg/2).ltoreq.6.0. In the treated state the alloys have very high specific mechanical strength (Vickers hardness/density&gt;70), even in the absence of any plastic deformation between quench and temper, thus justifying their use inter alia for components of complex shapes such as cast or stamped parts.

Al-Cu-Li-Mg alloys with very high specific mechanical strength

The invention relates to a process for obtaining crystals of intermetallic compounds, in particular isolated monocrystals, by cooling alloys in the molten state. The process involves using an alloy in the molten state which has a composition such that the first phase to crystallize during its solidification corresponds to the compound to be isolated, cooling it slowly by subjecting it to cyclic stirring and thermal cycling without attaining the temperature at which another solid phase appears then abruptly expelling the residual liquid. The process is used for obtaining large monophase primary crystals of compounds which melt congruently or incongruently, in particular compounds having symmetry of order 5 known as 'quasi-crystals'.

Process for obtaining crystals of intermetallic compounds, in particular

The invention concerns Al-base alloys with substantial proportions of Li and Si, containing, by weight:

Al alloys having high proportions of Li and Si and a process for

Heat treated and aged Al-base alloys containing lithium, magnesium and

The present invention relates to Al-base alloys essentially containing Li, Cu and Mg, and having high specific characteristics and a high degree of ductility. Their composition is as follows (% by weight):

Al-base alloys containing lithium, copper and magnesium and method

The invention concerns a method for minimizing deformation during rapid cooling of flat metallurigcal products such as sheets, strips, flattened portions, wide sections and the like. The method comprises rapidly cooling the product by means of a fluid (or mixtures of fluids) at temperature T.sub.F, comprising at least one vaporizable liquid, with modulation in a direction perpendicular to the direction of advance of the product, so as to impart different cooling speeds to the edges and the axis (case I) or to one edge and the other (case II). The technique may be completed by careful masking of the cooling in the zone for the rapid cooling action, or by controlled precooling prior to said rapid cooling. The method makes it possible to obtain the rapid cooling which is necessary e.g. in quenching operations, while at the same time minimizing the deformations or the internal stress level of flat products.

Method of modulated cooling to minimize deformation of flat

A process for the thermal treatment of wrought products made of an aluminum alloy of the 2000 series comprising by weight from 3.5 to 5% copper, from 0.2 to 1% magnesium, from 0.25 to 1.2% silicon, with a Si to Mg ratio greater than 0.8 comprising solution heat treatment, quenching treatment, ageing and tempering wherein the tempering treatment comprises at least two stages: (1) a main tempering treatment at a temperature higher than 225.degree. C. and lower than 280.degree. C. lasting between 6 seconds and 60 minutes and (2) a complementary tempering treatment at a temperature between 120.degree. and 175.degree. C. lasting between 4 and 192 hours. This process allows the compromise between the mechanical tensile characteristics and the resistance to intercrystalline and stress corrosion to be improved.

Process for the thermal treatment of aluminium - copper - magnesium -

A process for the thermal treatment of a relatively thick product made of a copper-containing aluminum alloy of the 7000 series, the invention involving a solution heat treatment, quenching and tempering in three steps:

Process for the thermal treatment of thick products made of

A process for the thermal treatment of thin products made of 7000 series aluminum alloys comprising a solution heat treatment, quenching treatment and a tempering treatment in three stages:

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St. Egreve, France

Bruno Dubost