Metal products with improved bond durability and related methods

Abstract

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.