Effect of Mg Composition on Aging Behavior of Al₂O₃ Particle Dispersed Al-Cu-Mg Alloy Composite Materials

The effect of Mg addition to the matrix of almina powder dispersed Al-4%Cu composite materials on the aging behavior has been investigated by means of microvickers hardness measurement and transmission electron microscopy. Age-hardening appeared in the composite materials with Mg addition when aged at 150°C, whereas the hardness decreased monotonically at 200°C aging. The aging behavior of the composite material with 0.6%Mg addition was the same as that of the ternary Al-4%Cu-0.6%Mg Alloy. In contrast, the aging process in the composite materials with 1.6 and 4%Mg addition differed remarkably from that of base alloy. That is, GP zone and were observed instead of GPB zone and S′ precipitates. Spinel was scarcely observed in the 0.6%Mg composite, and the amount of spinel near almina particle increased with an increase in the amount of Mg addition.