An aluminum alloy is a composition consisting mainly of aluminum to which other elements have been added. The alloy is made by mixing together the elements when aluminum is molten (liquid), which cools to form a homogeneous solid solution. The other elements may make up as much as 15 percent of the alloy by mass. Added elements include iron, copper, magnesium, silicon, and zinc. The addition of elements to the aluminum gives the alloy improved strength, workability, corrosion resistance, electrical conductivity, and/or density, compared with the pure metallic element. Aluminum alloys tend to be lightweight and corrosion resistant.
Most Popular Applications for Aluminum Alloys
> Aerospace and Automotive: Aerospace is one of the industries that is highly dependent on aluminum alloys, along with the automotive industry. In this particular case, aluminum alloys are becoming an increasingly important material. This is because it reduces the weight of the vehicle, thereby maximizing efficiency and fuel sustainability in the long run.
> Buildings: When constructing modern skyscrapers and buildings, it is very important to consider strength and safety. The added benefits of high corrosion resistance and low flammability, along with the natural insulating properties of aluminum, make it the perfect choice
> Electrical and Electronic Engineering: You will often find aluminum in electrical and electronic engineering applications as it does not cause any magnetic interference.
Wrought Alloy Designation System - We shall first consider the 4-digit wrought aluminum alloy identification system. The first digit (Xxxx) indicates the principal alloying element, which has been added to the aluminum alloy and is often used to describe the aluminum alloy series, i.e., 1000 series, 2000 series, 3000 series, up to 8000 series (see table 1).
The second single digit (xXxx), if different from 0, indicates a modification of the specific alloy, and the third and fourth digits (xxXX) are arbitrary numbers given to identify a specific alloy in the series. Example: In alloy 5183, the number 5 indicates that it is of the magnesium alloy series, the 1 indicates that it is the 1st modification to the original alloy 5083, and the 83 identifies it in the 5xxx series.
The only exception to this alloy numbering system is with the 1xxx series aluminum alloys (pure aluminums) in which case, the last 2 digits provide the minimum aluminum percentage above 99%, i.e., Alloy 13(50) (99.50% minimum aluminum).
WROUGHT ALUMINUM ALLOY DESIGNATION SYSTEM
Alloy Series | Principal Alloying Element |
1xxx | 99.000% Minimum Aluminum |
2xxx | Copper |
3xxx | Manganese |
4xxx | Silicon |
5xxx | Magnesium |
6xxx | Magnesium and Silicon |
7xxx | Zinc |
8xxx | Other Elements |
Cast Alloy Designation - The cast alloy designation system is based on a 3 digit-plus decimal designation xxx.x (i.e. 356.0). The first digit (Xxx.x) indicates the principal alloying element, which has been added to the aluminum alloy (see table 2).
CAST ALUMINUM ALLOY DESIGNATION SYSTEM
Alloy Series | Principal Alloying Element |
1xx.x | 99.000% minimum Aluminum |
2xx.x | Copper |
3xx.x | Silicon Plus Copper and/or Magnesium |
4xx.x | Silicon |
5xx.x | Magnesium |
6xx.x | Unused Series |
7xx.x | Zinc |
8xx.x | Tin |
9xx.x | Other Elements |
The second and third digits (xXX.x) are arbitrary numbers given to identify a specific alloy in the series. The number following the decimal point indicates whether the alloy is a casting (.0) or an ingot (.1 or .2). A capital letter prefix indicates a modification to a specific alloy.
Example: Alloy - A356.0 the capital A (Axxx.x) indicates a modification of alloy 356.0. The number 3 (A3xx.x) indicates that it is of the silicon plus copper and/or magnesium series. The 56 in (Ax56.0) identifies the alloy within the 3xx.x series, and the .0 (Axxx.0) indicates that it is a final shape casting and not an ingot.