The effects of thermo-mechanical parameters on the microstructure of Thixocast A356 aluminum alloy

In general, semi solid Thixocast (A356) alloys are consisted of extensive globular α-Al regions, which are surrounded by eutectic (β) phase. The better formability, higher toughness and structure free porosities, gas cavities and shrinkages are the important advantages of this globular structure. In addition the thermo-mechanical processing is known as one of the most effective processing techniques to control the final mechanical properties. Accordingly, in present work the effects of strain rate and the deformation temperature on the microstructure (morphology of Si phase) of Thixocast aluminum (A356) alloy have been studied. In this regard, hot compression tests at 450, 500 and 540 °C with strain rate of 0.0001, 0.0005, 0.001 and 0.01 s−1 have been performed. The results showed an extensive change in the morphology of eutectic Si fibers through breaking and spheroidization processes.