Dynamic mechanical response and thermal expansion of ceramic particle reinforced aluminium 6061 matrix composites

Abstract

The mechanical response of silicon carbide (SiC) particle and boron carbide (B₄C) particle reinforced aluminium 6061 alloy was studied under quasi-static and dynamic loading conditions, using an Instron universal testing machine and split Hopkinson pressure bar respectively. The stiffness and yield strength of the B₄C and SiC particle composites were significantly enhanced as compared to the unreinforced alloy. The strain hardening behaviour of the SiC particle reinforced composites was not significantly different as compared to that of the unreinforced alloy, at either low or high strain rates. On the other hand, the strength and strain hardening of the B₄C particle reinforced composites was significantly greater than that of the unreinforced alloy, at both low and high strain rates. Differences in the mechanical behaviour of the two composites was attributed to the differences in the strength of the reinforcing particles and bonding between the B₄C and SiC particles and the matrix alloy. Thermal expansion measurements carried out on the unreinforced alloy and composite samples attested to the findings of mechanical testing and microscopy.