High-Si reinforced Al matrix composites prepared by powder semi-solid squeeze

Abstract In this paper, high-Si reinforced Al matrix composites (H-Si/Al) with Si mass ratio 50–70% were successfully fabricated from the powder mixture of Si and Al by a novel route called as powder semi-solid squeeze. It is found that no Al–Si lamellar eutectic in the composites. As the Si content increases, fine Si particles in the H-Si/Al are reduced and the coarse Si particles may increase in size, or gather together to form twisted large particles and even form a space network structure. With the Si content ranging from 50% to 70%, The flexural strength varies between 248 and 179 MPa, the mean coefficient of thermal expansion from ambient temperature to 100 °C can be regulated between 11.32 and 7.55 × 10 −6 °C −1 , and the thermal conductivity varies between 140 and 120 W m −1  °C −1 , showing that H-Si/Al prepared by powder semi-solid squeeze have excellent mechanical and thermal properties.