Aluminium is enormously flexible, extremely usable and striking construction material due to anexclusive and invincibleblend of properties.Aluminium is the most commonly used metal in the world, next to iron. It is because aluminium has anexceptionalgrouping of striking properties. Aluminium's most important properties includegood thermal and electrical conductivity, easy machining, low weight, superior malleability,high strength and excellent corrosion resistance. Another plus point of Aluminium is that it can be recycled.
The properties of Aluminium include:
? Zero toxicity: Aluminium is the third most abundantly existing element in the Earth's crust, after oxygen and silicon. Aluminium compounds are also present naturally in the food.
? Weight: Aluminium has a density of 2.700 kg/m3 which is one third that of steel. It is very lightweight.
? Formability: Aluminium has excellentflexibilitywhich is a must for extrusion. Keeping the metal cold or hot, this property is also used in the bending and rolling of foils and strips, as well as inother developing operations.
? Strength: The tensile strengths of Aluminium alloys mostly range between 70 and 700 MPa. However, the alloys used in extrusion have ranges between 150 - 300 MPa. Aluminium does not become fragile at low temperatures unlike most steel grades. In fact, it gains strength at low temperatures and at higher temperatures, its strength decreases. Therefore for temperatures constantly above 100C, aluminium is affected to the level that the weakening must be taken care of.
? Conductivity: Aluminium is an outstanding conductor of electricity and heat. It is very useful as it is almost half the weight of copper conductor with same strength of conductivity.
? Reflectivity: Visible light and radiated heat are both reflected very well by Aluminium.
? Non-magnetic material: Aluminium is a non-magnetic (in fact paramagnetic) material. In order to avoid meddling of magnetic fields,it is used in most magnetic X-ray devices.
? Screening EMC: Electromagnetic radiations can be screened off or excluded by tight aluminium boxes.A material has good shielding qualities if it has good conductivity.
? Machining: Aluminium is worked up easily by use of most common machining techniques such asbending, milling, punching, cutting and drilling etc. Moreover, the energy required for machining is quite low.
? Linear expansion: Aluminium has a somewhat larger coefficient of linear expansion as compared with other metals. This needs to be taken care of in some applications.
? Corrosion resistance: Anextremely thin layer of oxide is formed as aluminium reacts with the oxygen in the air. Though it is very thin layer but it is dense and provides excellent protection to corrosion. The layer if damaged is self-repairing.Anodising raises the thickness of the oxide layer and thus increases the strength of the natural corrosion protection. When aluminium is used outside, layer of thickness 15 and 25is common.Aluminium is tremendouslytough in slightly acid and neutral surroundings.Corrosion is rapid in environments with high basicity or high acidity.
? Joining: Features enabling easy jointing are mostlymerged into profile design. Taping, Friction Stir Welding, Fusion welding, and bonding are all used for joining.
