Effect of rolling on microstructure behaviour, and mechanical properties of Mg-Al-Si alloys

Abstract

Magnesium-Aluminium-Silicon alloys with varying concentrations of Al (2–9 wt%), and 1 wt% Si are made using a fluxless method under an inert atmosphere in order to reduce the generation of gasses and also to see the effect of Al-content on microstructures and mechanical properties. The cast alloys were homogenized and then hot rolled at a temperature of 400 °C up to 90% reduction to examine the influence of rolling reduction on microstructural and mechanical properties. The Chinese script-type phases in as-cast conditions were sheared into spherical particles and distributed uniformly within the alloy matrix after hot rolling. The crystallite size decreases and dislocation density increases with increase in rolling reductions. The strength of the alloys increased by rolling reduction by at least 584% as compared to the as-cast alloys. It is further noted that even elongation of the cast alloys increases significantly after rolling. The strength of the alloy sheet follows Hall-Petch relationships with grain size. The Hall-Petch constants are in good agreement with the reported values. The obtained results were discussed in line with factrography, microstructural evaluation, grain size, and precipitation strengthening.