Role of Si at a lower level on the mechanical properties of Al-based automotive alloy

Silicon effect, at a lower level around 3.5 wt% on the tensile, impact, and fracture properties of Al-based automotive alloys has been investigated through T6 heat treatment. The results demonstrate that tensile strength increases in aged mainly due to development Al2Cu Mg2Si precipitates inside Al-matrix. alloy with higher amount Si shows formation Si-rich hinder dislocation movement causing values true strain change behaviour. 'The alloys? ductility decreases treatment temperature favour GP zones, ?'', ?', ? plus Q'' phase, then it finally after coarsening precipitates. Microstructural study confirms coarse grain boundary plate-like eutectic phase when is added. Fractography small dimple structure from Al dendrites crack initiates brittle particles.