Effect of processing parameters on microstructural and mechanical properties of aluminum-SiO2 nanocomposites produced by spark plasma sintering

Spark plasma sintering (SPS) is a powder metallurgy technique developed for consolidating metallic and/or ceramic particles in very short times. High heating and cooling rates can prevent excessive grain growth, favoring dcnsification. The spark plasma sintered materials' final properties are strongly related to the reinforcement types and percentages as well as to the processing parameters employed during synthesis. The present paper analyses the effect of 3 and 6 wt.% of nanosized SiO2 particles addition on the mechanical and microstructural behavior of Al-based metal matrix composites produced via SPS. The microstructural and mechanical behavior was analyzed as a function of the SPS parameters: heating rate, sintering temperature and pressure. Low percentages of silica particles are very effective for improving mechanical properties. High reinforcing percentages lead to agglomeration and drops in the composite's mechanical properties.