Materials for engineering, 3rd Edition - (Malestrom)
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Metals and alloys 87<br />
Table 3.2 International Alloy Designation System (IADS) <strong>for</strong> wrought aluminium alloys<br />
4-digit series (xxxx)<br />
Each wrought alloy is assigned a four-digit number of which the first digit is determined<br />
by the major alloying element(s) present, thus:<br />
Series<br />
Main alloying elements<br />
1xxx<br />
Unalloyed aluminium (99% Al minimum)<br />
2xxx<br />
Copper<br />
3xxx<br />
Manganese<br />
4xxx<br />
Silicon<br />
5xxx<br />
Magnesium<br />
6xxx<br />
Mg and Si<br />
7xxx<br />
Zinc<br />
8xxx<br />
Lithium<br />
9xxx<br />
Unused series<br />
Temper or heat treatment (also applied to Mg alloys)<br />
Suffix letters and digits are added to the alloy number in order to specify the mechanical<br />
properties of the alloy and the way in which the properties were achieved, thus:<br />
Suffix letter Basic condition<br />
F<br />
As-fabricated<br />
O<br />
Annealed wrought products<br />
H<br />
Cold worked (strain hardened)<br />
T<br />
Heat treated<br />
Suffix digits<br />
First digit<br />
Secondary treatment<br />
Second digit (H only) Degree of cold work<br />
Recourse to detailed specifications or to manufacturers’ literature is suggested when<br />
several digits are included in the temper designation.<br />
applied which stabilize them against this effect. These alloys are widely used<br />
in welded applications. Their corrosion resistance makes them suitable <strong>for</strong><br />
storage tanks and <strong>for</strong> marine hulls and superstructures. Fine-grained 5xxx<br />
alloys have also been used <strong>for</strong> superplastic <strong>for</strong>ming of panels.<br />
Heat-treatable alloys<br />
There are three important families:<br />
Aluminium–copper alloys (2xxx series). These can contain up to 6.8% copper<br />
and this system has been most widely studied as an example of age-hardening.<br />
For example, alloy 2219 (6.3% Cu) is available as sheet, plate and extrusions,<br />
as well as <strong>for</strong>gings, and it can be readily welded. It has relatively high<br />
strength in the peak-aged condition, but its peak hardness may be enhanced<br />
by about one third by strain hardening the quenched, supersaturated alloy<br />
be<strong>for</strong>e artificial ageing.<br />
The Al–Cu–Mg alloy known as Duralumin was the earliest age-hardening<br />
alloy to be developed, by Wilm in 1906. Alloy 2014 is a development of
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