HIGH-STRAIN RATE TENSILE PROPERTIES OF AN (AL2O3 PARTICLES)-(AL ALLOY6061-T6) METAL-MATRIX COMPOSITE

The metal matrix composite materials consist of 10, 15 and 20 vol.% al umina particles in an aluminium alloy 6061-T6 matrix. Specimens were t aken from hot-extruded rods and the tensile tests were carried out at various strain rates. High strain rate tests were performed by the spl it-Hopkinson-bar method. The fracture surfaces were observed with a sc anning electron microscope to understand the fracture mechanisms. From the results, it can be concluded that: (1) the alumina-reinforced com posites are more sensitive to strain rate than the unreinforced materi al. (2) the strain rate sensitivity of the ultimate tensile strength o f these composites increases with increasing temperature and (3) the a ddition of alumina particles will reduce the ductility of aluminium al loy 6061-T6, irrespective of the strain rate and temperature.