Influence of sintering temperature on the mechanical properties and thermal expansion of SiCp/Al–30Si composites

• SiCp/Al–30Si composites were fabricated by vacuum hot-pressing plus sintering.
• Effect of sintering temperature on the mechanical properties and CTE was studied.
• Silicon precipitate has a significant effect on the tensile strength and CTE.
• SiCp/Al–30Si composites show a good combination of mechanical properties and CTE.

In this investigation, SiCp/Al–30Si (SiC particle reinforced Al–30Si alloy matrix) composites were fabricated by vacuum hot-pressing plus sintering in the temperature range of 560–590 °C. The microstructure, phases and thermal expansion were studied using XRD, TEM, OM, SEM and thermo-mechanical analysis equipment. It is found that, as increasing the sintering temperature, the size of Si phase and relative density increased, the tensile strength first increased and then decreased, but the coefficient of thermal expansion failed to decrease. Overall, the results reveal that the sintering temperature has a significant effect on the tensile strength and thermal expansion of the composites.