Effect of Spark Plasma Sintering Temperature on the Microstructure and Thermophysical Properties of High-Silicon–Aluminum Composites

Spark plasma sintering is a process of rapid, low-temperature, and high-density sintering. Moreover, traditional sintering methods can solve the problems of large grain sizes and low densities. The sintering temperature plays a crucial role in influencing the physical properties of high-silicon–aluminum (Si-Al) composites. This work investigated the impact of temperature on the microstructure, interface, and physical properties of high-Si-Al composites by spark plasma sintering. The results demonstrate that when the powder was processed by ball milling at a sintering temperature of 565 °C, the material exhibited the densest microstructure with minimal pore formation. The average size of the silicon phase is the smallest. The material’s thermal conductivity is 134.6 W/m·K, the thermal expansion coefficient is 8.55 × 10−6 K−1, the Brinell hardness is 219 HBW, the density is 2.415 g/cm3, and the density reaches 97.75%. An appropriate sintering temperature facilitates particle rearrangement and dissolution–precipitation processes, enhancing the material structure and performance.