Aluminum alloy for forming an axisymmetric article

A method of forming an integral wheel structure, the integral wheel structure comprising a hub having an axis of rotation, a plurality of equal length spokes extending radially outwardly from the hub, in a plane that is perpendicular to the axis of rotation of the hub, to a circumferential rim at the radially outer ends of the spokes, the circumferential rim having a predetermined width, extending transverse to the plane of the spokes, and having a thickness and shape for sealing engagement with a flexible pneumatic tire to be placed on the rim for use of the integral wheel structure, the integral wheel structure being formed of an aluminum-based alloy by the method comprising:

• injecting a mold-filling volume of a molten aluminum-based alloy into a cavity of a mold, the mold being maintained at a temperature in the range of 180° C. to 260° C., the molten aluminum-based alloy being at a temperature in the range of 650° C. to 750° C., and maintaining a predetermined pressure on the molten aluminum-based alloy to force the molten alloy into full conformance with the surfaces of the cavity, the molten aluminum base alloy having a composition consisting essentially, by weight, of 3.0-4.0% zinc, 1.8-2.5% silicon, 1.3-2.0% magnesium, 0.2-0.5% manganese, 0.15-0.2% titanium, 0.05% maximum copper, 0.1% maximum iron, and the balance aluminum, the surfaces of the cavity substantially defining predetermined shapes of the hub and spokes and a pre-form shape of the circumferential rim that has a larger thickness and shorter width than the desired shape of the rim in the integral wheel structure to be formed;
• cooling the molten aluminum-based alloy to form a solid wheel pre-form shape and removing the solid wheel pre-form shape from the facing mold members;
• heating the solid wheel pre-form shape in air to soften the solid wheel pre-form shape for shaping of the circumferential rim of the wheel;
• applying a mechanical forming force to the pre-form shape of the circumferential rim of the wheel at a predetermined temperature above ambient temperature to obtain solid-state flow of the aluminum-based alloy metal and to form the circumferential rim into its intended shape in the integral wheel structure.

A method of forming an integral article of manufacture having an axisymmetrical shape, the integral article comprising a center portion having a central axis, a body structure extending radially outwardly from the center portion, in a plane that is perpendicular to the central axis of the center portion, to a circumferential perimeter, and an axisymmetric member, axisymmetric with respect to the axis of the center portion, extending a predetermined length outwardly from and transverse to the radial plane of the body structure, the axisymmetric member having a thickness and shape, the integral article being formed of an aluminum-based alloy by the method comprising:

• injecting a volume of a molten aluminum-based alloy into a mold cavity and filling the mold cavity, the mold cavity having surfaces formed by separable, facing mold members and maintaining a predetermined pressure on the molten aluminum-based alloy to force the molten alloy into full conformance with the surfaces of the cavity, the molten aluminum base alloy having a composition consisting essentially, by weight, of 3.0-4.0% zinc, 1.8-2.5% silicon, 1.3-2.0% magnesium, 0.2-0.5% manganese, 0.15-0.2% titanium, 0.05% maximum copper, 0.1% maximum iron, and the balance aluminum, the surfaces of the mold cavity substantially defining predetermined shapes of the center portion and body structure, and a pre-form shape of the axisymmetric member, the pre-form shape having a larger thickness and shorter length than the desired shape of the axisymmetric member in the integral article;
• cooling the molten aluminum-based alloy to form a solid article pre-form shape and removing the solid article pre-form shape from the facing mold members;
• and
• applying a mechanical forming force to the pre-form shape of the axisymmetric member of the article at a predetermined temperature above ambient temperature to obtain progressive incremental solid-state flow of the aluminum-based alloy metal to form the axisymmetric member into its intended final shape in the formed integral article.