Study the Mechanical Properties of Aluminium Alloy A356 with Semi Solid (Stir Casting) Process and Heat Treatments T6

Abstract

The purpose of this research was to investigate mechanical properties of A356 mixed aluminium alloy which was solidified via semi-solid casting with stirring speed of 300, 500, and 700 rpm for 5, 10, and 15 minutes. After that, it was poured into a die cast aluminium at 680 Celsius and put into the water at 580 Celsius. Then T6 heat treatment was applied with a sheet obtained from stir casting process. In this experiment, solution treatment was used at 540 Celsius for 1 hour. The sheet was put into the water at room temperature and taken into artificial aging treatment at 160 Celsius for 1 6 and 8 hours. The results indicated that the maximum hardness value was 71.56 HB when stirring at 300 rpm for 10 minutes and its microstructure of A356 alloy was globular. For the sheet gathered from the T6 heat treatment, it found that the artificial aging at 160 Celsius for 1 6 and 8 hours provided the hardness values at 83.31 91.62 and 99.52 HB respectively. Its microstructure after applying the T6 heat treatment was more globular. Similarly, the face of eutectic silicon was more globular because the eutectic silicon was better transmitted into aluminium content. This would impede dislocation motion and increase the hardness value.