In 2018 Apple revealed that the MacBook Air's enclosure was using 100% recycled aluminum. This revelation was met with thunderous applause from the audience. Below is the video of the Apple keynote that touched on this single point.

This past Thursday the US Patent & Trademark Office published two patent application from Apple relating to this topic of recycled aluminum. The first patent is titled "Heat-Treatable Aluminum Alloy made from used Beverage can Scrap; The second is titled "Cosmetic Aluminum Alloys made from Recycled Aluminum Scrap." While the aluminum that is used in MacBooks is derived from recycled aluminum pop and beer can scrap, the "alloy" to create the MacBook actually contains other recycled metals as both patents describe.

According to Apple, the disclosure is directed to aluminum alloys that can incorporate used beverage can scrap. The disclosure also relates to a clad including a recycled aluminum substrate and a surface layer.

Apple further notes that it is very difficult to make a cosmetic aluminum alloy from recycled material, such as UBC scrap. However, it is possible to clad a surface layer and a substrate, such as a substrate formed from a recycled material such as UBC scrap. The surface layer can have various properties that provide cosmetic appeal. The substrate can include previously used aluminum, such as UBC scrap, that can increase the total amount of aluminum recycling. The clad can be designed such that a property or properties of the substrate are within a range of properties of the surface layer.

A custom alloy can be designed to incorporate high levels of UBC scrap. The custom alloy can also be designed to be compatible with conventional cladding processes and to be compatible with cosmetic alloys for the surface layer(s) in a clad configuration. FIG. 1A illustrates a clad configuration in accordance with a first embodiment of the disclosure. As shown, a clad 100A may include a surface layer 102 over a substrate 104, such as a substrate formed from recycled aluminum including UBC scrap or an alloy or a custom alloy incorporating UBC scrap.

Apple's patent FIG. 1A below illustrates a clad configuration. As shown, a clad (#100A) may include a surface layer (#102) over a substrate (#104), such as a substrate formed from recycled aluminum including UBC scrap or an alloy or a custom alloy incorporating UBC scrap; FIG. 2A illustrates hot rolling to form a clad; FIG. 2B illustrates an optical image of the cross-section of FIG. 2A; FIG. 2C illustrates a coil formed of the clad of FIG. 2A.

Apple's patent FIG. 3 above illustrates a flow chart including steps for fabricating a product from recycled UBC scrap; FIG. 4 illustrates estimated yield strengths versus silicon (Si) composition of a custom aluminum alloy.

The first patent titled "Heat-Treatable Aluminum Alloy made from used Beverage can Scrap," goes into more detail with the following headers:

• The Clad
•  Custom Alloys Used for Substrate Materials
• Silicon
• Magnesium
• Iron
• Copper
• Manganese
• Impurities introduced to Recycled Alloys
• Processing
• Examples
• Used Beverage Can (UBC) Scrap Compositions

The second patent titled "Cosmetic Aluminum Alloys made from Recycled Aluminum Scrap" goes into more detail with the following headers:

• Alloys Made from Market Scrap
• Cu Content
• Mn Content
• Cr Content
• Zn Content
• Fe Content
• Ti Content
• Si Content and Mg Content
• Additional Non-Aluminum Elements
• Cosmetic Appeal
• Mechanical Properties
• Grain Aspect Ratio
• Corrosion Resistance
• Cyclic Polarization Test
• Metastable Pitting
• Salt Fog Testing
• Examples
• Process for Cleaning and Removing Oxides from Scrap

Both patents will be appreciated by metallurgical engineers and enthusiastic geeks. For finer details, review Apple's patent applications 20210087656 and 20210087664. To a certain extent these are patents fulfilled.