METAL PRODUCTS WITH IMPROVED BOND DURABILITY AND RELATED METHODS
Aluminum alloy products having a bulk and a micro-grained subsurface structure are described. The aluminum alloy products may exhibit superior bonding character and may comprise or have a silicon-containing layer thereon. The bulk may include a matrix including grains of an aluminum alloy and may comprise aluminum and one or more alloying elements such as zinc, magnesium, copper, chromium, silicon, iron, or manganese. The micro-grained subsurface structure may be substantially devoid of one or more defects (e.g., voids, transfer cracks, or fissures) or organics, oils, hydrocarbons, soils, inorganic residues, rolled-in oxides, or anodic oxides, which may commonly be present in rolled near-surface microstructures. The micro-grained subsurface structure may include or have thereon a first oxide layer having a thickness of from 1 nm to 20 nm. Methods of making aluminum alloy products are also described.
1 . An aluminum alloy product, comprising:
a bulk, wherein the bulk comprises a bulk grain structure including grains of an aluminum alloy, the aluminum alloy comprising:
aluminum; and
one or more alloying elements selected from the group consisting of zinc, magnesium, copper, chromium, silicon, iron, and manganese;
a first surface region including a near-surface microstructure (NSM) of a thickness less than 500 nm;
a second surface region free of the NSM, wherein the second surface region comprises an oxide layer; and
a micro-grained subsurface structure present between the oxide layer and the bulk, wherein the micro-grained subsurface structure:
has a thickness from 1 nm to 2 μm;
is devoid or substantially devoid of one or more compositional defects, wherein the one or more compositional defects comprise organics, oils, hydrocarbons, soils, inorganic residues, rolled-in oxides, or anodic oxides; and
comprises a grain structure that is different from the bulk grain structure, wherein the grain structure comprises aluminum alloy grains having an average diameter of from 10 nm to 500 nm.
2 . The aluminum alloy product of claim 1 , wherein the oxide layer has a thickness from 1 nm to 20 nm.
3 . (canceled)
4 . (canceled)
5 . The aluminum alloy product of claim 1 , wherein the NSM comprises one or more compositional defects, wherein the one or more compositional defects comprise organics, oils, hydrocarbons, soils, inorganic residues, rolled-in oxides, or anodic oxides.
6 . The aluminum alloy product of claim 1 , wherein a ratio of the first surface region to the second surface region is less than 50%.
7 . (canceled)
8 . The aluminum alloy product of claim 1 , wherein the micro-grained subsurface structure further comprises precipitates having an average diameter of from 10 nm to 2 μm, wherein the precipitates comprise one or more alloying elements selected from the group consisting of zinc, magnesium, copper, chromium, silicon, iron, and manganese.
9 . The aluminum alloy product of claim 1 , further comprising a silicon-containing layer on the micro-grained subsurface structure, wherein the silicon-containing layer modifies a portion of bonding sites within the micro-grained subsurface structure.
10 . The aluminum alloy product of claim 1 , wherein a weight percent of aluminum in the micro-grained subsurface structure is less than a weight percent of aluminum in the bulk.
11 . (canceled)
12 . The aluminum alloy product of claim 1 , wherein a concentration of magnesium and zinc in the aluminum alloy is less than 20 wt. %, wherein a ratio of zinc to magnesium in the concentration is from 0.1 to 10.0.
13 . (canceled)
14 . The aluminum alloy product of claim 1 , wherein the micro-grained subsurface structure comprises more structural defects than the bulk, wherein structural defects correspond to or comprise voids, transfer cracks, or fissures.
15 . (canceled)
16 . The aluminum alloy product of claim 1 , wherein the micro-grained subsurface structure comprises a grain structure homogeneity or an alloying element distribution homogeneity different from that of the bulk.
17 . A method of treating an aluminum alloy product, comprising:
providing a rolled aluminum alloy product comprising:
a bulk, wherein the bulk comprises a bulk grain structure including grains of an aluminum alloy, the aluminum alloy comprising:
aluminum; and
one or more alloying elements selected from the group consisting of zinc, magnesium, copper, chromium, silicon, iron, and manganese; and
a near-surface microstructure (NSM) having a thickness of greater than 500 nm;
modifying the NSM to generate:
a first surface region including a near-surface microstructure (NSM) of a thickness less than 500 nm;
a second surface region free of the NSM, wherein the second surface region comprises an oxide layer; and
a micro-grained subsurface structure between the oxide layer and the bulk, wherein the micro-grained subsurface structure:
has a thickness from 1 nm to 2 μm;
is devoid or substantially devoid of one or more compositional defects, wherein the one or more compositional defects comprise organics, oils, hydrocarbons, soils, inorganic residues, rolled-in oxides, or anodic oxides; and
comprises a grain structure that is different from the bulk grain structure, wherein the grain structure comprises aluminum alloy grains having an average diameter of from 10 nm to 500 nm.
18 . The method of claim 17 , wherein the oxide layer has a thickness from 1 nm to 20 nm.
19 . (canceled)
20 . The method of claim 17 , wherein the oxide layer is devoid or substantially devoid of one or more defects.
21 . (canceled)
22 . The method of claim 17 , wherein a ratio of the first surface region to the second surface region is less than 50%.
23 . The method of claim 17 , wherein the first surface region and the second surface region are discontinuous.
24 . (canceled)
25 . (canceled)
26 . The method of claim 17 , wherein a weight percent of aluminum in the micro-grained subsurface structure is less than a weight percent of aluminum in the bulk.
27 . The method of claim 17 , wherein a concentration of magnesium in the bulk is greater than in the micro-grained subsurface structure, wherein a concentration of copper in the bulk is greater than in the micro-grained subsurface structure, or wherein a concentration of zinc in the bulk is greater than in the micro-grained subsurface structure.
28 . The method of claim 17 , wherein the micro-grained subsurface structure provides a bond durability of from 22 cycles to 100 cycles, or more, according to a FLTM BV 101-07 standard test.
29 . (canceled)
30 . The method of claim 17 , wherein modifying the NSM comprises depositing a silicon-containing layer when generating the micro-grained subsurface structure or coating at least a portion of the micro-grained subsurface structure with a silicon-containing layer, wherein the silicon-containing layer modifies a portion of bonding sites within the micro-grained subsurface structure.
31 . The method of claim 17 , wherein modifying comprises subjecting the NSM to mechanical alteration, wherein the mechanical alteration comprises one or more of:
grinding the NSM,
physically ablating the NSM;
grit-blasting the NSM;
laser ablating the NSM;
sand blasting the NSM; or
polishing the NSM.