C-tec Constellium Technology Center

Melanie Ollat

Jean-Christophe Ehrstrom

A method for thermomechanical treatment of wrought products made of a 2000 series aluminum alloy comprising, in % by weight, Cu 3.5-5.8; Mg 0.2-1.5; Mn≤0.9; Fe≤0.15; Si≤0.15; Zr≤0.25; Ag≤0.8; Zn≤0.8; Ti 0.02-0.15; unavoidable impurities≤0.05 each and ≤0.15 total; remainder aluminum, enabling an improvement in the resistance to corrosion under stress. It includes a tempering consisting of two sequences. The first sequence is defined by a maximum temperature Tcomprised between 130° C. and 180° C. and by a hold time at a temperature comprised between 130° C. and 180° C. which equates to an equivalent duration tcalculated at 160° C. comprised between 10 h and 80 h. The second sequence is defined by a temperature T(t) lower than Tand a hold time tat a temperature comprised between 100° C. and 130° C., which equates to an equivalent time tcalculated at 160° C. such that t° comprised between 0.3% and 15% of the equivalent duration t° calculated for the first sequence.

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Ruy-Montceau, France

Melanie Ollat