Definition
A sheet of high-strength aluminum alloy that has a thin layer of pure aluminum bonded to each side during manufacture. The pure aluminum outer layers resist corrosion, while the strong alloy core provides the structural strength needed for aircraft skin and other airframe parts.
Plain English
A strong aluminum alloy sheet sandwiched between two thin layers of pure aluminum. The outer layers protect the inside from rust-like corrosion, and the inside provides strength.
Context Anchor
Seen in aircraft structure and maintenance discussions, especially for skin panels, sheet-metal repairs, and corrosion inspection.
Derivation
The name is a contraction of 'aluminum-clad.' To 'clad' something means to cover it with a protective layer, so Alclad literally means 'covered with aluminum.' That covering is what gives the material its corrosion resistance.
Why Pilots Care
Alclad aluminum is used for aircraft skins and structural panels because the coating prevents corrosion without adding significant weight, helping keep the airframe safe and durable over time.
Analogy
It is like a strong metal sheet wearing a thin protective coat, except the coat is metal too and is bonded on during manufacture.
Intuition Check
Do not think of Alclad aluminum as aluminum that was simply painted or coated later. The protective aluminum layer is part of the sheet as manufactured.
Example Sentence 1
The technician noted that the scratch on the wing skin had cut through the Alclad layer, exposing the alloy beneath.
Example Sentence 2
Mechanics prefer Alclad aluminum for exterior repairs because the pure aluminum coating protects the underlying alloy from oxidation.