Enhanced age-hardening response of Al–4Mg–1Cu (wt.%) microalloyed with Ag and Si

Microalloying of an Al–4Mg–1Cu alloy (wt.%) with Si and Ag produced an enhanced age-hardening response, increasing peak hardness whilst also accelerating precipitation kinetics due to a modified precipitation process. The addition of Si stabilizes Guinier–Preston–Bagaryasky zones and suppresses T-phase formation. In contrast, the alloy modified with Si + Ag featured extensive precipitation of the Z-phase as platelets on matrix {1 1 1}Al planes, whilst S-phase formation was suppressed.