HIGH-STRENGTH ALUMINIUM-BASED ALLOY AND METHOD FOR OBTAINING ITEMS FROM IT Russian patent published in 2012 - IPC C22C21/10 C22F1/04 

FIELD: metallurgy.

SUBSTANCE: group of inventions can be used at manufacture of semi-finished products in the form of forgings, formings, pressed rods and channels, rolled plates and sheets from high-strength alloys of Al-Zn-Mg-Cu system, which are intended to be used in power structures of aerospace equipment and transport means, on which stringent strength, crack resistance, fatigue life, corrosion resistance requirements are imposed. In order to solve the set task, high-strength alloy on the basis of aluminium, which contains the following, wt %, is proposed: Zn 6.2-8.0, Mg 1.5-2.5, Cu 0.8-1.2, Zr 0.05-0.15, Fe 0.03-0.15, Ti 0.01-0.06, at least one element of the group of metals: Ag 0.01-0.5, Sc 0.01-0.35, Ca 0.0001-0.01, Al and inevitable impurities are the rest. In particular version of alloy the inevitable impurities include not more than 0.05 of Si, Mn, Cr, Ni and not more than 0.01 of Na, H₂, O₂, B, P. Method for obtaining an item from this alloy involves ingot casting, its homogenisation, hot deformation and strengthening heat treatment of the item, which includes hardening and staged ageing; at that, during the ingot casting there performed is melt purification by blowing with argon or mixture of argon with chlorine and out-of-furnace purification using rotor and/or filtering devices, and homogenisation is performed as per one-stage mode at temperature which is by 55-130°C lower than unbalanced solidus (t_u._s.) temperature of this alloy with exposure during 8-36 h or as per two-stage mode at temperature at the first stage at the temperature which is by 175-280°C lower than t_u.s. temperature, and at the second stage at the temperature which is by 75-125°C lower than t_u.s., with exposure at each stage to 24-36 h; hot deformation is performed at temperature of 300-420°C, hardening is performed at temperature which is by 50-120°C lower than t_u.s. during the time determined with the item thickness, with further cooling to temperature of not more than 80°C.

EFFECT: improving the set of mechanical and corrosive characteristics, and characteristics of crack resistance, life time and manufacturability.

10 cl, 1 tbl