DYNAMIC-MECHANICAL RESPONSE AND THERMAL-EXPANSION OF CERAMIC PARTICLE-REINFORCED ALUMINUM 6061 MATRIX COMPOSITES

The mechanical response of silicon carbide (SiC) particle and boron ca rbide (B4C) particle reinforced aluminium 6061 alloy was studied under quasi-static and dynamic loading conditions, using an Instron univers al testing machine and split Hopkinson pressure bar respectively. The stiffness and yield strength of the B4C and SiC particle composites we re significantly enhanced as compared to the unreinforced alloy. The s train hardening behaviour of the SiC particle reinforced composites wa s not significantly different as compared to that of the unreinforced alloy, at either low or high strain rates. On the other hand, the stre ngth and strain hardening of the B4C particle reinforced composites wa s significantly greater than that of the unreinforced alloy, at both l ow and high strain rates. Differences in the mechanical behaviour of t he two composites was attributed to the differences in the strength of the reinforcing particles and bonding between the B4C and SiC particl es 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.