Effect of Cryorolling on Microstructure, Conductivities, and Mechanical Properties of a Cast Near-Eutectic Al-Si-Fe-Mg Alloy

The effects of cryorolling on the microstructure, thermal and electrical conductivities, and mechanical properties of near-eutectic Al-Si-Fe-Mg alloys were investigated by different cryorolling reductions. The results indicated that as the cryorolling reduction increased, the aspect ratio and the grain size of Si phase decrease gradually by fractured and elongated. The dislocation density gradually increases because the cryorolling process restrains the recovery and recrystallization of the alloys. The electron transfer is facilitated by the refinement of the Si phase, while the high dislocation density hinders the phonon transfer, their combined action leads to an increase in the electrical conductivity of the alloy, while the thermal conductivity first increases and then decreases. Meanwhile, the Si phase refinement and dislocation strengthening enhance the hardness, strength and plasticity of the alloy, respectively.