The naming of Aluminum alloys is based on a combination of factors that typically include the alloying elements, their relative proportions, and sometimes additional information about the alloy's characteristics or applications. Understanding the names of aluminum alloys can provide valuable information about their composition and properties. 

1. Alloy Series:  Aluminum alloys are categorized into different series based on their main alloying elements:

• Series 1xxx: These alloys are almost pure aluminum, with a minimum aluminum content of 99%.
• Series 2xxx: These alloys contain Copper as the primary alloying element.
• Series 3xxx: These alloys have manganese as the primary alloying element.
• Series 4xxx: These alloys contain silicon as the primary alloying element.
• Series 5xxx: These alloys primarily feature magnesium as the main alloying element.
• Series 6xxx: These alloys have magnesium and silicon as the primary alloying elements.
• Series 7xxx: These alloys contain Zinc as the main alloying element.
• Series 8xxx: These alloys consist of other elements not covered by the previous series.
• Series 9xxx: These alloys are used for experimental or developmental purposes.

2. Numeric Designation: 

• Within each alloy series, aluminum alloys are assigned a four-digit or five-digit numeric designation.
• The first digit indicates the principal alloying element or group of elements:
• For example, alloy 6061 belongs to the 6xxx series, with magnesium and silicon as the primary alloying elements.
• The following digits provide more specific information about the alloy:
• They may indicate refinements in composition, impurity limits, or special characteristics.
• For example, alloy 6061 may have additional digits (e.g., 6061-T6), where the suffix "T6" denotes a specific temper or heat treatment applied to the alloy.

3. Additional Suffixes: Some aluminum alloys may have additional suffixes or letters added to their numeric designation to indicate specific characteristics, processes, or applications:

• "H" indicates that the alloy has undergone a strain-hardening process.
• "O" indicates that the alloy is annealed (fully softened).
• "F" indicates that the alloy is as-fabricated (without any special heat treatment).
• "T" followed by a digit denotes a specific temper or heat treatment.
• Other suffixes may be used to denote specific properties, treatments, or applications.

These numbers indicate that in the manufacturing process elements have been added to the alloys and made a special group of these metals. The ANSI and AA (Aluminum Association) naming system uses a four-digit numbering mechanism for used alloys and a three-digit numbering system for cast alloys. The first number represents the Metal grouping and the most important alloying element added to the alloy. In addition to alloy numbering, the type of heat treatment process or alloy fabrication process is also the basis for specifying an alloy. For this naming, English letters are used at the end of the alloy name, for example, AA 2024-T4.  This designation is called ANSI H35.1 under the American National Standard and is called the "Defined Temper System" and is used for all production methods. Depending on the production process, one of the letters is used, which we introduce in the following:

• F for no change and mode of production
• O for annealed mode
• H for hardened strain mode (cooled work)
• W for heat treatment of solubilization
• T is used for other heat treatments such as hard deposition in naming alloys.

For the first number in the HXX category

• H1 hardened strain without heat treatment
• H2 strain hardened and slightly annealed
• H3 strain hardened and stabilized by low-temperature heat treatment

The second number in the HXX category (if any) indicates the amount of stiffness obtained relative to the maximum stiffness in that stiffening operation.

• HX2 indicates a hardness of 4.1 of the maximum hardness.
• HX4 indicates a hardness of 2.1 of the maximum hardness.
• HX6 indicates a hardness of 3.4 maximum hardness.
• HX8 indicates maximum stiffness.
• HX9 indicates higher hardness than maximum hardness.

T is for the condition where the alloys have been heating treated. This mode indicates stable tempers (except for the F, O, or H modes, as opposed to the W naming mode).

• T1 cooled from a shaping process, with high temperature and aged naturally
• T2 cooled from a shaping process, with high temperature, the work cooled and aged naturally
• T3 heat treatment of soluble cooled and naturally aged work
• T4 Heat treatment of soluble and naturally aged type
• T5 is cooled by a high-temperature forming process and artificially aged
• T6 heat treatment of artificially solubilized and aged type
• T7 heat treatment of solubilized and stable type
• T8 heat treatment of solubilized type artificially cooled, and aged work
• T9 heat treatment of solubilized type, artificially aged and then cooled work
• T10 cooled by a high-temperature forming process, artificially cooled, and aged work

In some cases, T-category extensions have more than one digit, such as AA 224-T351 or AA 6061-T651, in which case the following should be considered. TX51 stands for stress relief after stretching after heat treatment of the first number (x number). It's important to note that the naming conventions for aluminum alloys are standardized but may vary slightly depending on different specifications and standards. Therefore, it's advisable to consult the appropriate standards or references for detailed information about specific aluminum alloys. Understanding the names of aluminum alloys allows engineers, manufacturers, and users to identify the alloy's composition, properties, and potential applications. It helps in selecting the right alloy for specific requirements and ensures consistent communication within the industry.