Patent ID: 8444777

Claim:
A high-strength and high-ductility Al alloy, which is obtained by a rapid solidification process comprising: (a) subjecting a molten metal, comprising: Al; from 5 to 12 mass % of Zn; from 2 to 4 mass % of Mg; and from 1 to 2 mass % of Cu; at least one of: from 0.01 to 0.1 mass % of Ag and from 0.1 to 0.5 mass % in total of at least one selected from the group consisting of Si, Fe, Mn, Cr, Co, Ni, Zr, Ti and V; and an unavoidable impurity, to spray forming with an inert gas having a gas/metal ratio of 6 to 15 Nm 3 /kg, such that a cooling and solidification rate is controlled by the gas/metal ratio of the inert gas blown into the molten metal, to form a preform; (b) placing and vacuum-encapsulating the preform in a metal vessel; (c) solidifying the preform by hot extrusion; and then (d) applying a heat treatment thereto to obtain an Al alloy, wherein: an amount of oxygen contained in the Al alloy as measured by an extraction residue method using hot phenol is 0.1 mass % or less in terms of oxygen in a solid residue which is separated and extracted from the Al alloy and has a size of 0.1 μm or more; and the Al alloy has a tensile strength of 600 MPa or more, and (i) an elongation of 15% or more when the tensile strength is 600 MPa or more and less than 800 MPa, or (ii) an elongation of 10% or more when the tensile strength is 800 MPa or more.