IMPACT TENSILE PROPERTIES IN AL-MG-SI BASE ALLOYS FOR AUTOMOTIVE USE

Abstract

Effect of alloy composition on impact tensile properties [Formula: see text] in Al - Mg - Si base alloys was investigated by means of the split Hopkinson pressure bar method. As a result of the impact test, it was proved that the nominal stress for 5% plastic strain was not changed by changing the strain rate regardless of the alloy composition. In the impact test, the elongation was decreased with increasing the amount of excess Si , while that was increased by the addition of Cu . Fractography revealed that the reduction of the elongation in the excess Si alloy was caused by the change of the fracture mode from the mixture of transgranular and intergranular fracture to the intergranular fracture.