Effect of SiC particle size on the physical and mechanical properties of extruded Al matrix nanocomposites

• As the amount of SiC particles increase, the composite’s densification declines.
• Increasing the amount and reducing the size of SiC lead to reduced thermal conductivity.
• The SiC particles size decreases, the grain size and the distribution of reinforcement decreases.
• Increasing the amount and reducing the size of SiC promote high hardness in the composite.
• The finer particle size and increasing the amount of SiC presents greater compressive strength.

In this work, the effect of SiC particle size and its amount on both physical and mechanical properties of Al matrix composite were investigated. SiC of particle size 70 nm, 10 μm and 40 μm, and Al powder of particle size 60 μm were used. Composites of Al with 5 and 10 wt.% SiC were fabricated by powder metallurgy technique followed by hot extrusion. Phase composition and microstructure were characterized. Relative density, thermal conductivity, hardness and compression strength were studied. The results showed that the X-ray diffraction (XRD) analysis indicated that the dominant components were Al and SiC. Densification and thermal conductivity of the composites decreased with increasing the amount of SiC and increased with increasing SiC particle size. Scanning electron microscope (SEM) studies showed that the distribution of the reinforced particle was uniform. Increasing the amount of SiC leads to higher hardness and consequently improves the compressive strength of Al–SiC composite. Moreover, as the SiC particle size decreases, hardness and compressive strength increase. The use of fine SiC particles has a similar effect on both hardness and compressive strength.