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Even the briefest of Google searches for 'advantages of aluminium' will present a plethora of statements extolling the virtues of aluminium. Among its many attributes are said to be its lightness, strength, flexibility, durability and corrosion resistance. At first sighting the uninitiated may be forgiven for asking, 'how can this be?' How is it possible that one metal can possess all of these qualities? The good news is all of these 'wish list' properties can be accurately attributed to aluminium, or rather aluminium alloy. The key word here is 'alloy'. Alloys are the other metals that are added to aluminium, in relatively small amounts, to produce the required performance characteristics (along with post-production processess that include cold working, heat treatment, etc.). It is a combination of these factors that mark aluminium alloys out as such truly versatile materials. To fully appreciate the performance enhancing benefits of alloying aluminium let's consider Aluminium in its pure state. Unalloyed aluminium has a yield stress (the stress at which a material begins to deform plastically) of around 7-10MPa. The range of aluminium alloys, normally used within the architectural industry, usually produce somewhere in the region of 100-200MPa. without necessarily being a graduate engineer you get the drift! The addition of alloy to aluminium is perfomance enhancing and could be equated with an athlete consuming chemical supplements to build muscle mass, but with only desirable side effects. It should be understood that the mechanical properties of a particular aluminium alloy will vary considerably dependent on the form type, be it aluminium extrusions, sheet, casting etc., in addition to the amount of work hardening, heat and solution treatment, applied post production. For instance let's take a look at specification 6063 (a commonly used extruded architectural alloy) to see how beneficial the addition of small quantities of alloy are. This alloy grade (when heated) is sufficiently plastic to allow for the production of small intricate profile shapes and after cooling, for subsequent cold working techniques to be carried out e.g. rolling into curves and rings. At the same time this aluminium alloy is strong and rigid enough to be selected as suitable for panel hanging systems. Independent tests have demonstrated the interlocking profiles (illustrated below) to be capable of suspending the equivalent weight of a small car! As an added bonus, 6063 alloy is also a suitable grade for the anodising process.
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aluminium, extrusion, extrusions,
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