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2
Aluminum and Its Alloys
J. Randolph Kissell
TGB Partnership
Hillsborough, North Carolina
Introduction
This chapter describes aluminum and its alloys and their mechanical,
physical, and corrosion resistance properties. Information is also pro-
vided on aluminum product forms and their fabrication, joining, and
finishing. A glossary of terms used in this chapter is given in Section
, and useful references on aluminum are listed at the end of the
chapter.
History
When a six-pound aluminum cap was placed at the top of the Wash-
ington Monument upon pletion in 1884, aluminum was so rare
that it was considered a precious metal and a novelty. In less than 100
years, however, aluminum became the most widely used metal after
iron. This meteoric rise to prominence is a result of the qualities of the
metal and its alloys as well as its economic advantages.
In nature, aluminum is found bined with other elements,
mainly oxygen and silicon, in reddish, clay-like deposits of bauxite
near the Earth’s surface. Of the 92 elements that occur naturally in
the Earth’s crust, aluminum is the third most abundant at 8%, sur-
passed only by oxygen (47%) and silicon (28%). Because it is so diffi-
cult to extract pure aluminum from its natural state, however, it
wasn’t until 1807 that it was identified by Sir Humphry Davy of En-
gland, who named it aluminum after alumine, the name the Romans
gave the metal they believed was present in clay. Davy essfully
produced small, relatively pure amounts of potassium but failed to iso-
late aluminum.
In 1825, Hans Oersted of Denmark finally produced a small lump of
aluminum by heating potassium amalgam with aluminum chloride.
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Chapter 2
Napoleon III of France, intrigued with possible military applications
of the metal, promoted research leading to Sainte-Claire Devil