Cegedur Societe De Transformation De L'aluminium Pechiney

Cegedur Societe De Transformation De L'aluminum Pechiney

Cegedur Pechiney

Societe Metallurgieque De Gerzat

Cegedur Societe De Transformation

Cegedur Societe De Transformation De L'aluminum Perchiney

Philippe Meyer

Bruno Dubost

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 relates to aluminum alloy products containing 1 to 3.5% Li, up to 4% Cu, up to 5% Mg and up to 3% Zr, and additions of Mn, Cr and/or Zr, in which:

Products based on aluminum containing lithium which can be used in their

The invention relates to a process for improving the surface condition of Li-containing Al alloy products. According to the process, heating at a temperature exceeding 300.degree. C. takes place in an atmosphere containing, in volume percent, 5 to 98% CO.sub.2, 2.ltoreq.dry air.ltoreq.95% and the remainder water. The process prevents the appearance of surface pitting and reduces the depth of the Li-depleted surface zone.

Process for the heat treatment of Al alloys containing Li with a view to

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 relates to hollow bodies for gas under pressure manufactured from an aluminum alloy containing Zn, Cu and Mg as principal alloying elements and intended in particular for the production of metal bottles for pressurized gas. The hollow bodies are manufactured from an alloy consisting essentially of (in % by weight):

Al-base alloy hollow bodies under pressure

The invention is directed to a process for plating Al alloys containing lithium by hot co-rolling under the usual heating conditions, in the air. The process comprises effecting controlled oxidation of the core alloy by heating in the air at between 450.degree. C. and 550.degree. C. for a period of time such that the depth affected by the surface loss of Li is between 50 and 700 .mu.m. The core is then treated mechanically or chemically to remove the surface oxides with a loss of alloy less than 30 .mu.m. An assembly of the core and platings is then co-rolled with reheating to a temperature of less than 500.degree. C. for less than 24 hours. The result is perfect adhesion of the core to the surface platings.

Process for plating Al alloys containing Li, by hot co-rolling

The invention concerns a process for producing products of Al-base alloys essentially containing Li, Mg and Cu as main alloy elements and having a high level of ductility and isotropy. The process comprises subjecting the homogenized product to a 'tepid' transformation operation at from 100.degree. to 420.degree. C. The intermediate annealing operations, if required, are carried out in the range of from 200.degree. to 550.degree. C. The rate of cooling after the intermediate annealing operations is generally kept at from 1500.degree. C./second to 30.degree. C./hour. The isotropy and ductility of the resulting products are considerably improved in comparison with the prior art processes.

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Voiron, France

Philippe Meyer