Aluminium Design and Construction John Dwight

Deflection
Because of the lower modulus, elastic deflection becomes more of a
factor than it is in steel. This is often a consideration in beam design.
1.4 HISTORY
The following is an outline of how, in the century from 1845 to 1945,
aluminium became the second most important industrial metal [3].
1.4.1 The precious metal stage
In 1825 the Danish scientist Hans Oersted succeeded in isolating minute
particles of metallic aluminium. Having satisfied himself that the metal
existed he lost interest, and returned to his main field of study, electromagnetism.
Two years later Friedrich Wöhler, professor of chemistry at
Göttingen University in Germany, began to repeat Oersted’s experiments.
He persisted for 20 years and eventually produced the first actual nuggets
of aluminium, big enough to reveal some of the metal’s special properties,
especially its lightness and brightness. A piece of the aluminium he
produced is on display in the university museum at Göttingen.
The step from scientific curiosity to commercial product was made
in the 1850s by the French chemist Henri Ste-Claire Deville, a professor
at the Sorbonne University in Paris. Having read of Wöhler’s work,
he interested Napoleon III in the new metal and received funding to
develop it commercially. Wöhler’s chemical process for obtaining
aluminium had relied on potassium, the high cost of which meant
that it would never be of commercial interest. Ste-Claire Deville’s
approach was to develop an economic method for obtaining sodium,
and use this instead of potassium in the Wöhler process. He was thus
able to produce aluminium which, if hardly cheap, would be a practical
metal for some applications. A dozen small bars were displayed at an
exposition in Paris in 1855, dubbed ‘silver from clay’. The first
aluminium artefact is said to have been a rattle made for the infant
son of Napoleon III.
Over the next 30 years the Deville process was exploited in several
countries, including Britain, to produce what was at that stage a high
cost luxury metal. An example of its use was for spoons at royal banquets
instead of gold, and it was also employed in cast form for small statues.
A purity of about 97% is recorded for metal produced at the Nanterres
factory outside Paris.
Copyright 1999 by Taylor & Francis Group. All Rights Reserved.