Investigating the Role of Pouring Temperature, Heat Treatment and Mold Preheating Temperature on the Hardness and Microstructure of the Inner Surface of Al-15Mg2Si In Situ Composite Pipe Fabricated by Centrifugal Casting Method

This study aims to place Mg2Si reinforcing particles in the inner wall of aluminum matrix composite tube and optimize the microstructure and hardness of the mentioned wall using temperature parameters. Upon application of Al-Si alloy, creation of in-situ Mg2Si particles in this alloy system, and production of the pipe as a result of the low density of Mg2Si particles based on the centrifugal casting method, these reinforcing particles would be accumulated in the inner wall of the pipe. In this study, the effect of dissolution, aging, mold preheating, and pouring temperature on the hardness of the inner wall ofAl-15 wt. % Mg2Si alloy was investigated, and the most optimal manufacturing conditions as well the interaction among the variables were determined using Design Expert software to achieve the highest hardness. Of note, the most effective variable among the mentioned variables was heat treatment temperature, and the best temperature was about 535 °C. According to the findings, the best pouring temperature was obtained as around 700 °C; hence, a higher temperature is needed to preheat the mold to obtain reinforcement with uniform placement.