Abstract: In a method of extruding a 6000-series-type aluminum alloy by casting, homogenizing, extruding and optionally, aging and/or heat treating, an alloy composition is provided having silicon 0.6-1.2 wt. %, magnesium 0.7-1.2 wt. %, copper 0.3-1.1 wt. %, manganese 0.1-0.8 wt. %, zirconium 0.05-0.25 wt. %, up to 0.5 wt. % iron, up to 0.15 wt. % chromium, up to 0.25 wt. % zinc, up to 0.10 wt. % titanium with the balance aluminum and incidental impurities wherein an effective amount of zirconium, in combination with effective amounts of manganese, produces a fibrous grain structure which contributes to a combination of high strength and fracture toughness in the extruded alloy. The fibrous grain structure also permits improvements in forming the extrusion by enabling lower temperatures to be utilized during the homogenization step.

Abstract: Aluminum based alloy primarily for use in aircraft and aerospace components consists essentially of the composition: 2.60 to 3.30 weight percent copper, 0.0 to 0.50 weight percent manganese, 1.30 to 1.65 weight percent lithium, 0.0 to 1.8 percent magnesium, and from 0.0 to 1.5 weight percent of grain refinement elements selected from the group consisting of zirconium, and chromium. Up to about 0.5 wt. % zinc and up to about 1.5 wt. % titanium may also be present. Minor impurities may also be present. These alloys exhibit an improved combination of characteristics including low density, high strength, high corrosion resistance and good fracture toughness.