Wrought Aluminium

Aluminium is very well available in the form of bauxite. The high price results from the large amount of energy, needed for the extraction process: 148 MJ/kg Al. Recycling of  used material takes considerably less energy: 10 MJ/kg Al. Therefore recycling is favourable, although alloying elements may cause problems. Wrought Al alloys represent about 85% of Al applications. Compared to steel, both density and Young's modulus of Al are a factor 3 lower. Precipitation hardening can bring the strength in the range of carbon steels, dependent on alloy type, but precipitation hardened alloys can show drawbacks in corrosion resistance, formability and weldability.  Generally, corrosion resistance is good, especially for pure Al and Al-Mg alloys, as a result of a closed protective oxide layer. The crystal structure of Al is FCC, which offers a good (cold) formability. The structure of wrought alloys offers better mechanical properties than cast alloys, caused by anisotropy. Machining of Al  is hard because of the high plasticity.