Elevated temperature tensile properties of an extruded aluminium alloy reinforced with SiCp

Elevated temperature tensile properties of AlSi7Mg (Al-7 %Si-0.7 %Mg) and its composites with 10 and 20 vol.% SiCP in the as-extruded form were investigated. The cast ingots of the matrix alloy and the composites were produced by the permanent die casting technique and extruded at 480 degrees C using an extrusion ratio of 10:1. The high-temperature tensile tests were carried out over the temperature range from 25 to 430 degrees C. Mechanical properties after extrusion show that the composite samples have strength values superior to that of the matrix alloy at ambient temperature. At elevated temperatures the results indicate that the composites exhibit good strength retention up to 300 degrees C, above which the strengthening effect of SiCP disappears as the temperature is increased. The strain rate sensitivity "m" was observed to be 0.11 for the matrix alloy, 0.13 and 0.07 for the composites with 10 and 20 vol.% SiCP respectively, at a test temperature of 430 degrees C in the strain rate range from 4 x 10(-5) to 4 x 10(-2) s(-1).