A method of forming a heat treatable aluminum alloy, the method comprising: (a) forming a melt consisting of: 1.0 to 8.0 weight percent copper; 0.2 to 4.0 weight percent magnesium; at least one first element selected from the group consisting of 0.1 to 6.0 weight percent erbium, 0.1 to 10.0 weight percent thulium, 0.1 to 15.0 weight percent ytterbium, and 0.1 to 12.0 weight percent lutetium; at least one second element selected from the group comprising 0.1 to 4.0 weight percent gadolinium, 0.1 to 4.0 weight percent yttrium, 0.05 to 1.0 weight percent zirconium, 0.05 to 2.0 weight percent titanium, 0.05 to 2.0 weight percent hafnium, and 0.05 to 1.0 weight percent niobium; optionally comprising at least one of 0.001 weight percent to 0.1 weight percent sodium, 0.001 weight percent to 0.1 weight calcium, 0.001 weight percent to 0.1 weight percent strontium, 0.001 weight percent to 0.1 weight percent antimony, 0.001 weight percent to 0.1 weight percent barium and 0.001 weight percent to 0.1 weight percent phosphorus; comprising no more than 0.1 weight percent iron, 0.1 weight percent chromium, 0.1 weight percent manganese, 0.1 weight percent vanadium, 0.1 weight percent cobalt, and 0.1 weight percent nickel; comprising no more than 1.0 weight percent total impurities; and the balance being substantially aluminum with unavoidable impurities; (b) solidifying the melt to form a solid body; and (c) heat treating the solid body; wherein the solidifying comprises a rapid solidification process in which the cooling rate is greater than 10 3 °C/second; and wherein the heat treating comprises: solution heat treatment at 800°F (426°C) to 1100°F (593°C) for thirty minutes to four hours; quenching; and aging at 200°F (93°C) to 600°F (316°C) for two to forty-eight hours. (a) forming a melt consisting of: 1.0 to 8.0 weight percent copper; 0.2 to 4.0 weight percent magnesium; at least one first element selected from the group consisting of 0.1 to 6.0 weight percent erbium, 0.1 to 10.0 weight percent thulium, 0.1 to 15.0 weight percent ytterbium, and 0.1 to 12.0 weight percent lutetium; at least one second element selected from the group comprising 0.1 to 4.0 weight percent gadolinium, 0.1 to 4.0 weight percent yttrium, 0.05 to 1.0 weight percent zirconium, 0.05 to 2.0 weight percent titanium, 0.05 to 2.0 weight percent hafnium, and 0.05 to 1.0 weight percent niobium; optionally comprising at least one of 0.001 weight percent to 0.1 weight percent sodium, 0.001 weight percent to 0.1 weight calcium, 0.001 weight percent to 0.1 weight percent strontium, 0.001 weight percent to 0.1 weight percent antimony, 0.001 weight percent to 0.1 weight percent barium and 0.001 weight percent to 0.1 weight percent phosphorus; comprising no more than 0.1 weight percent iron, 0.1 weight percent chromium, 0.1 weight percent manganese, 0.1 weight percent vanadium, 0.1 weight percent cobalt, and 0.1 weight percent nickel; comprising no more than 1.0 weight percent total impurities; and the balance being substantially aluminum with unavoidable impurities; 1.0 to 8.0 weight percent copper; 0.2 to 4.0 weight percent magnesium; at least one first element selected from the group consisting of 0.1 to 6.0 weight percent erbium, 0.1 to 10.0 weight percent thulium, 0.1 to 15.0 weight percent ytterbium, and 0.1 to 12.0 weight percent lutetium; at least one second element selected from the group comprising 0.1 to 4.0 weight percent gadolinium, 0.1 to 4.0 weight percent yttrium, 0.05 to 1.0 weight percent zirconium, 0.05 to 2.0 weight percent titanium, 0.05 to 2.0 weight percent hafnium, and 0.05 to 1.0 weight percent niobium; (b) solidifying the melt to form a solid body; and (c) heat treating the solid body; wherein the solidifying comprises a rapid solidification process in which the cooling rate is greater than 10 3 °C/second; and wherein the heat treating comprises: solution heat treatment at 800°F (426°C) to 1100°F (593°C) for thirty minutes to four hours; quenching; and aging at 200°F (93°C) to 600°F (316°C) for two to forty-eight hours. solution heat treatment at 800°F (426°C) to 1100°F (593°C) for thirty minutes to four hours; quenching; and aging at 200°F (93°C) to 600°F (316°C) for two to forty-eight hours.