The effects of ternary alloying additions on solute-drag creep in Al-Mg alloys

Effects of ternary additions of Zn, Fe, and Cu on solute-drag creep and duc tility in Al-Mg alloys are studied. The materials studied are, in wt. pct., Al 2Mg-5Zn, Al-3Mg-5Zn, Al-4Mg-5Zn, Al-3Mg-0.11Fe, Al-3Mg-0.27Fe, Al-3Mg 0.40Fe, Al-3Mg-0.50Cu, Al-3Mg-1.02Cu, Al-3Mg-1.52Cu, and Al-3Mg-2.15Cu. Experimental data show that ternary Zn additions do not have an adverse ef fect on solute-drag creep in Al-Mg alloys, but increase the sensitivity of stress exponent, n, to Mg content. Transitions to power-law breakdown in the Al xMg-5Zn materials are discussed. Ternary Fe and Cu additions increases n during solute-drag creep. Ductilities of over 100% are consistently achieved in the Al-xMg-5Zn and Al-3Mg-xFe materials. Age hardenability during natu ral aging and simulated paint-bake cycle are studied for the Al-xMg-5Zn and Al-3Mg-xCu materials. Zn creates a significant paint-bake response, while the effect of Cu is small for a simulated paint-bake cycle.