Effects of the Si element on the microstructure and mechanical properties of an Al/FMG/SiC hybrid composite

Abstract

Enhancing the mechanical properties of metal matrix composites can be achieved through the modification of the chemical composition of the matrix. However, the specific role of silicon (Si) as an important alloying element in the context of Al matrix hybrid composites simultaneously reinforced with metallic glass and ceramic particles has not been extensively studied. Therefore, this present study aimed to investigate the effects of Si element on the microstructure and mechanical properties of an Al–Si matrix composite reinforced with SiC and Fe-based metallic glass (FMG) particles. The composite was fabricated using a powder metallurgy approach. The amount of Si was selected to position the resultant alloy solidus temperature in the super-cooled liquid region of the FMG reinforcing particles. Results showed that a small amount of Si formed an Al-rich solid solution in the Al matrix, while the rest was observed as Si-rich regions in the microstructure. Adding Si to the matrix improved densification behavior and reduced porosity content during sintering, resulting in a more homogeneous distribution of reinforcing particles. The compressive yield strength and hardness of the composite with Si in its composition were 82% and 74% higher, respectively, than the same composite without Si, confirming the effectiveness of incorporating Si in the matrix.