SEDL / STP / STP580-EB / STP32337S

Heat-Treatable Cladding for New Aluminum Alloy 7050-T76 Sheet

Staley, JT
Section head, Alcoa Laboratories, Alcoa Technical Center, Alcoa Center, Pa.

Pages: 12    Published: Jan 1975

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Abstract

Four alloys were evaluated as candidates for a cladding on aluminum alloy 7050-T76 sheet. An alloy containing nominally 5 percent zinc, 1.2 percent magnesium, 0.1 percent zirconium, 0.1 percent maximum silicon, and 0.1 percent maximum iron, balance aluminum, provided good electrochemical protection to alloy 7050, and the composite of 7050-T76 clad with this alloy developed a useful combination of static and cyclic mechanical properties. Composites of 7050-T76 sheet clad with alloys containing higher amounts of zinc and magnesium developed comparable static mechanical properties and greater fatigue strengths, but were susceptible to stress-corrosion cracking of the cladding, and, consequently, are unacceptable.