Why are clad aluminum alloys used in aircraft construction?

Clad aluminum alloys are employed in aircraft construction primarily to inhibit corrosion. These alloys are coated with a thin layer of pure aluminum, which acts as a protective barrier against corrosion mechanisms such as oxidation and environmental exposure. The pure aluminum layer protects the underlying alloy from corrosive elements, which can significantly extend the lifespan of the aircraft structural components and maintain their strength and integrity over time.

While all factors mentioned in the other choices can play a role in aircraft design and materials selection, corrosion resistance is a critical concern in aviation due to the harsh environmental conditions that aircraft typically encounter. By using clad aluminum alloys, manufacturers can effectively address the potential for corrosion without significantly compromising the material properties necessary for aircraft performance.