A Study on the Microstructure Change with Modification and Cast-forging in Hypereutectic Al-Si Alloys

For application of cast-forging process with Al-Si hypereutectic alloys, casting experiments are carried out by adding P and Sr to Al-Si hypereutectic alloys for eutectic and primary Si refinement treatment. We experimented on the mechanical properties according to microstructural changes, forging ability test and also investigated the mechanical properties after forging. The finest microstructure could be observed respectively when 0.075 wt.% Sr and 0.1 wt.% P were added. In this case, tensile strength and elongation increased much more than no addition as casting. After high temperature deformation simulation test with grain refinement specimens was carried out about 60 N/mm of specimen was confirmed. After hot forging, tensile strength and elongation wear increased. It was considered that casting defect was removed by compressive working.