ULTRA-FINE ALUMINUM ALLOYS FOR HIGH-STRENGTH ARTICLES MADE UNDER SUPERPLASTICITY CONDITIONS, AND A METHOD OF PRODUCING ARTICLES Russian patent published in 2020 - IPC C22F1/53 C22C21/10 

FIELD: metallurgy.

SUBSTANCE: invention relates to non-ferrous metallurgy, namely, to production and processing of ultra-fine aluminum alloys, and can be used for production of high-strength articles in conditions of superplasticity by isothermal extrusion, volume or sheet forging, as well as molding. Ultra-fine aluminum alloy of 7000 series of Al-Zn-Mg and Al-Zn-Mg-Cu system is characterized by a structure having average grain size of not more than 500 nm, wherein at least 60 % of grains have large-angle boundaries disoriented relative to adjacent grains at angles of 15 degrees or more, on which grain-boundary segregations are formed by atoms of basic alloying elements Zn, Mg, Cu or at least one of them, and hardening phase particles η-MgZn₂ with size of 10-20 nm, wherein the grains consist of an aluminum matrix containing nanoclusters uniformly distributed in the bulk of grains, formed by atoms of alloying elements Zn, Mg, Cu or at least one of them, with size of 2-5 nm, and particles of the strengthening phase η-MgZn₂ with size of 10-20 nm. Method of obtaining article from ultra-fine aluminum alloy of series 7000 of system Al-Zn-Mg and Al-Zn-Mg-Cu includes production of workpiece, billet annealing at 460-490 °C, hardening into water, intensive plastic deformation at temperature not higher than 200 °C with total true accumulated deformation e≥4 and shaping superplastic deformation at temperature not higher than 250 °C, deformation rate 10^-2-10^-5 s^-1 with maximum deformation value of not less than 300 %.

EFFECT: invention increases level of mechanical strength of aluminum alloys before and after shaping processing in conditions of superplasticity and fabricate high-strength articles by extrusion, volumetric or sheet forging, as well as molding.

5 cl, 4 dwg, 1 ex