High strength, high toughness, weldable, ballistic quality, castable aluminum alloy, heat treatment for same and articles produced from same

Abstract

An aluminum alloy cast product is composed of:

Cu

5.00-6.75

weight %,

Mg

0.05-0.50

weight %,

Mn

0.05-0.65

weight %,

Ti

0.05-0.40

weight %,

Ag

0.00-0.40

weight %,

Cr

0.00-0.20

weight %,

V

0.00-0.40

weight %,

Zr

0.00-0.30

weight %,

Fe

<0.15

weight %,

Si

<0.15

weight %,

Ni

<0.05

weight %,

Zn

<0.05

weight %,

impurities

<0.05

each weight %,

<0.25

total weight %,

Al

balance

Such an aluminum alloy cast product is heat treated to eliminate the interdendritic network of second phase particles. The heat treatment of such an aluminum alloy casting alloy includes solution heat treatment before hot isostatic pressing.

Description

FIELD OF THE INVENTION [0001] This invention relates to 1) an aluminum alloy for casting operations, such as sand, investment or permanent mold casting operations, 2) a heat treatment process for aluminum alloys and 3) the application of the newly invented aluminum alloy casting alloy for cast products for racing, aerospace and military (land, sea and air) applications. TERMINOLOGYT4:solution heat treated and then naturally aged to a substantially stablecondition; applies to products that are not cold worked after solution heattreatment, or in which the effect of cold work in flattening or straightening maynot be recognized in mechanical property limitsT6:solution heat treated and then artificially aged; applies to products that are notcold worked after solution heat treatment, or in which the effect of cold workin flattening or straightening may not be recognized in mechanical propertylimitsT61:solution heat treated and then artificially aged to develop maximum strengthwith adequa...

AI Technical Summary

Benefits of technology

[0026] The aluminum alloy casting alloy of the present invention is desirable because it is weldable and retains the desired properties when heat treated after welding.

Problems solved by technology

However, none of these aluminum alloy casting alloys have the desirable combination of high strength, high ductility, high toughness, good resistance to stress corrosion cracking, good weldability and good castability (i.e. good resistance to hot tearing and good fluidity).

Hot tearing is a catastrophic event that occurs during the casting process and renders the cast product unusable.

“Spongy” areas, which have high levels of porosity, due to poor feeding will have low strength and hot spots caused by the combination of thick and thin sections will have high tensile contraction stresses that promote hot tearing.

Aluminum alloy casting alloys 354, C355, A356 and A357 have good castability but do not have good mechanical properties.

Aluminum alloy casting alloys A201 and A206 have good mechanical properties but do not have good castability, good resistance to stress corrosion cracking or good weldability.

Both A201 and A206 alloy have poor fluidity and poor resistance to hot tearing during casting.

There are numerous aluminum alloy wrought alloys that have attractive properties for aerospace and military applications but products from these aluminum alloys must be machined from plate or billet, which is extremely time consuming and costly, or must be forged into useful shapes.

Because “stretching” is a cold working process, the benefit of stretching is lost if the product is welded or heat treated after “stretching”.

Further, products that are cast to shape cannot be “stretched”.

This patent does not disclose information on the properties of castings made from the disclosed alloy.

One of the reasons that castings typically have inferior properties compared to wrought products is porosity.

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