At extremely high temperatures (200-250°C) aluminum alloys tend to lose
some of their strength. However, at subzero temperatures, their strength
increases while retaining their ductility, making aluminum an extremely useful
Aluminum alloys have a strong resistance to corrosion
which is a result of an oxide skin that forms as a result of reactions with the
atmosphere. This corrosive skin protects aluminum from most chemicals,
weathering conditions, and even many acids, however alkaline substances are
known to penetrate the protective skin and corrode the metal.
Aluminum also has a rather high electrical conductivity, making it useful as a
conductor. Copper is the more widely used conductor, having a conductivity of
approximately 161% that of aluminum. Aluminum connectors have a tendency
to become loosened after repeated usage leading to arcing and fire, which
requires extra precaution and special design when using aluminum wiring in buildings.
Aluminum is a very versatile metal and can be cast in any form known. It can be
rolled, stamped, drawn, spun, roll-formed, hammered and forged. The metal can
be extruded into a variety of shapes, and can be turned, milled, and bored in the
machining process. Aluminum can riveted, welded, brazed, or resin bonded. For
most applications, aluminum needs no protective coating as it can be finished to
look good, however it is often anodized to improve color and strength.