The effect of Ge addition on Al–3.5Cu–0.4Mg (wt.%) alloy

A trace (0.2 wt.%) addition of Ge significantly increased both the strength and elongation of Al–3.5Cu–0.4 Mg alloy. An aged Al–3.5Cu–0.4 Mg–0.2Ge (wt.%) alloy revealed good tensile properties after being exposed at 150 °C. Transmission electron microscopy observations showed that these properties are closely correlated to the high-density microstructure of nanoscale precipitates and the good coarsening resistance of those precipitates; Ge stimulated the formation of nanoscale precipitates and suppressed the formation of S′ precipitates in aged Al–3.5Cu–0.4 Mg–0.2Ge (wt.%) alloy.