Influence of cryorolling on microstructure and mechanical properties of a cast hypoeutectic Al-Si alloy

Cast Al-Si alloys often show poor tensile strength, less ductility and poor fatigue performance due to cast microstructure and presence of porosity. An attempt has been made to improve mechanical properties of a cast hypoeutectic Al-Si alloy (A356) by cryorolling. As cast Al-Si alloy (A356) processed by cryorolling at different imposed strain levels was subjected to microstructural analysis and mechanical testing. Cryorolling resulted in break up and uniform distribution of coarse acicular eutectic particles in the aluminium matrix, elimination of casting porosity, microstructural refinement and significant accumulation of dislocation density. These microstructural changes resulted in significant improvement in the strength (248%) and ductility (37%). The influence of cryorolling on mechanism of microstructural modification, strengthening mechanism and failure mechanism are studied in detail.