Effects of Squeeze Casting Parameters ‎on the Microstructure ‎Characteristics of ‎ZAMAK5 ‎Reinforced with Alumina Preform ‎Composite

The study investigated the impact of pouring temperature and squeeze pressure on the microstructure of a Zamak 5 alloy reinforced with alumina preform composite. The experiment involved conducting squeeze casting at three pouring temperatures (450, 500, and 550 degrees Celsius) and three pressures (15, 25, and 35 MPa) using a hydraulic press with a 20-ton capacity and a cylindrical chamber mold (30 mm in diameter and 60 mm in height). Subsequently, the solidification microstructure, casting defects, and hardness of the manufactured composites were assessed. Microstructural analysis was carried out using optical and scanning electron microscopes with elemental and image analyzers. Hardness was measured using the Brinell method. The findings revealed that certain microstructural characteristics, such as the secondary dendritic arms spacing and the number of eutectic cells, decreased with increasing squeeze pressure and pouring temperature. The study demonstrated that the effect of squeeze pressure, particularly up to 25 MPa, had a more pronounced influence compared to pouring temperature. Furthermore, it was observed that higher pressure and melt temperature facilitated a stronger connection between the base metal and the preform, resulting in proper filling of the preform's pores. Based on the microstructural analysis and hardness evaluation, the minimum squeeze pressure of 25 MPa and a pouring temperature of over 500 degrees Celsius provide suitable conditions for producing composites.