Understanding Aluminium Alloys: A Beginner’s Guide to the 1xxx to 8xxx Series

Aluminium alloys are named and grouped so you can tell what they’re made of and how they behave. Each alloy gets a number that shows its basic composition and purpose. This helps engineers, fabricators and buyers understand what the metal does and how it compares to others.

The number system covers a range of materials, from highly pure aluminium (99%+) in the 1xxx series to high-strength alloys used in aerospace, such as those in the 7xxx series. Knowing this system makes it easier to talk about alloys and choose the right one for your project, whether you’re sourcing materials on AL Biz or deciding what works best for manufacturing.

This guide explains the 1xxx to 8xxx series in simple terms.

What Are Aluminium Alloys?

Aluminium is a versatile, lightweight metal commonly used across many industries. Pure aluminium, however, isn’t always strong enough for demanding applications. This is where aluminium alloys come in. By adding other elements like copper, magnesium and silicon, manufacturers can improve the metal’s properties to suit specific needs.

Aluminium alloys are classified into series based on their primary alloying elements, which are selected to enhance specific properties like strength, corrosion resistance, or formability. Each series offers a unique combination of properties, making it easier to choose the right material for specific applications.

The AL Biz platform helps connect businesses to suppliers, ensuring easy access to a variety of aluminium alloys and allowing for a seamless sourcing process. If you have any aluminium buying requirements, you can post your RFQ on our B2B marketplace.

Properties and Applications of 1xxx to 8xxx Series Aluminium Alloys

In this guide, we’ll explore the most popular and commonly used alloys from each series, along with their key characteristics and applications.

1xxx Series: Pure Aluminium

The 1xxx series alloys are made from at least 99% pure aluminium. These are known for their excellent conductivity and resistance to corrosion, making them ideal for applications where these properties are essential.

Properties: High thermal and electrical conductivity, excellent corrosion resistance, good workability and low strength.

Popular Alloys:

• 1050: Used primarily for electrical conductors like wires and cables.
• 1100: Common in chemical equipment, food processing and decorative applications.

Applications:

• Electrical conductors (wires, cables)
• Food and chemical containers
• Architectural materials (roofing, cladding)

2xxx Series: Aluminium-Copper Alloys

The 2xxx series alloys are alloyed with copper, offering high strength for aerospace and military applications. However, they are more susceptible to corrosion and often require protective coatings or anodising.

Properties: High strength, good machinability, lower corrosion resistance than other series and heat treatable.

Popular Alloys:

• 2024: Known for its high strength-to-weight ratio, commonly used in aircraft structures.
• 2011: Popular for precision machining applications.

Applications:

• Aircraft components (wing structures, fuselage)
• Military parts (missile casings)
• Automotive parts requiring high strength

3xxx Series: Aluminium-Manganese Alloys

The 3xxx series alloys are known for their good corrosion resistance, particularly in general atmospheric and mild marine environments. However, they are not as resistant as the 5xxx series in saltwater but offer good formability and weldability.

Properties: Excellent corrosion resistance, especially in marine environments, good formability, moderate strength.

Popular Alloys:

• 3003: Used in roofing, siding and cooking utensils.
• 3105: Commonly found in residential siding and mobile homes.

Applications:

• Roofing and siding
• Cookware
• Heat exchangers

4xxx Series: Aluminium-Silicon Alloys

The 4xxx series alloys are chosen for their low melting points and good wear resistance. Due to their silicon content, this alloy is ideal for casting applications where fluidity and easy shaping are of utmost importance.

Properties: Low melting point, good wear resistance, excellent casting ability and easy machinability.

Popular Alloys:

• 4045: Frequently used in automotive heat exchangers.
• 4032: Commonly used for engine components like pistons and cylinder heads.

Applications:

• Engine components (pistons, engine blocks)
• Welding wire
• Heat exchangers in automotive and industrial applications

5xxx Series: Aluminium-Magnesium Alloys

The 5xxx series alloys are highly resistant to corrosion, especially in saltwater environments. This makes them popular for marine and automotive applications.

Properties: Exceptional corrosion resistance, good strength, good weldability.

Popular Alloys:

• 5052: Known for excellent corrosion resistance, used in marine environments.
• 5083: Often used in shipbuilding and pressure vessels due to its superior strength.

Applications:

• Marine equipment (boats, ships)
• Automotive components (fuel tanks, bumpers)
• Pressure vessels

6xxx Series: Aluminium-Magnesium-Silicon Alloys

The 6xxx series alloys are the most versatile, combining good strength, formability and excellent corrosion resistance. These alloys are widely used in structural applications.

Properties: Excellent balance of strength, formability and corrosion resistance.

Popular Alloys:

• 6061: Commonly used in structural and industrial applications.
• 6063: Primarily used in architectural applications like window frames.

Applications:

• Structural applications (bridges, buildings)
• Automotive (frames, parts)
• Aerospace (aircraft fuselage)

7xxx Series: Aluminium-Zinc Alloys

The 7xxx series alloys provide the highest strength of all aluminium alloys, making them ideal for aerospace and military uses. These alloys can be heat-treated to improve strength.

Properties: Very high strength, lower corrosion resistance, heat treatable.

Popular Alloys:

• 7075: Known for its high strength, widely used in aerospace and military applications.
• 7050: A choice for aerospace parts requiring strength and good corrosion resistance.

Applications:

• Aerospace parts (aircraft wings, fuselage)
• Military equipment (missile bodies, rocket casings)
• Sporting goods (bicycles, skis)

8xxx Series: Miscellaneous Alloys

The 8xxx series includes various alloys designed for specific applications, often with a combination of elements not found in other series.

Properties: Designed for niche applications with unique combinations of elements.

Popular Alloys:

• 8006: Used primarily in food packaging, particularly aluminium foil.
• 8090: A high-strength, lightweight alloy used in aerospace.

Applications:

• Packaging (aluminium foil)
• Electrical cables
• Aerospace (lightweight structural components)

Unwrought Aluminium Alloys Naming System

The four-digit aluminium alloy number system provides detailed information about the alloy’s composition, its primary or dominant alloying elements and its sequence of modifications within the series.

The First Number: This indicates the primary alloying element group the alloy belongs to. Each number corresponds to a particular element:

1 = Pure aluminium
2 = Aluminium-copper alloys
3 = Aluminium-manganese alloys
4 = Aluminium-silicon alloys
5 = Aluminium-magnesium alloys
6 = Aluminium-magnesium-silicon alloys
7 = Aluminium-zinc alloys
8 = Miscellaneous alloys (with various elements)

For example, in 5183, the “5” tells you that magnesium is the primary alloying element.

The Second Number: This represents the modification number of the alloy within that specific alloy group. It shows how many times the base alloy has been modified or improved.

In 5183, the “1” indicates that it is the first modification of the base alloy, which was originally 5083.

The Last Two Digits: These indicate the sequence in which the alloy was created within its series. The last two digits are typically used to show the order of development for alloys within that series.

In 5183, the “83” refers to the 83rd modification or version of the original alloy.

So, 5183 means:

• It’s part of the 5xxx series (magnesium alloys),
• The “1” shows it’s the first modification of 5083 and
• The “83” signifies the sequence in which it was developed within the 5xxx series.

Note: Unlike other series, the 1xxx series alloys (pure aluminium) have a unique numbering system where the last two digits indicate the minimum aluminium content percentage, rather than the modification number.

For example, 1350 means 99.50% minimum aluminium, while 1100 typically contains 99% aluminium.

Wrought vs Cast Aluminium Alloys: What’s the Difference?

Aluminium alloys are broadly grouped as wrought or cast based on how they are processed.

• Wrought alloys are mechanically worked (rolled, extruded, forged, drawn, etc.). They are usually designated with four‑digit numbers (like 6061 or 7075) and are selected where strength, formability and durability are needed.
• Cast alloys are produced by pouring molten metal into moulds. They use a three‑digit‑plus‑decimal designation system (e.g., 356.0). Cast alloys are chosen for parts with complex shapes, such as automotive housings, cylinder heads, pump bodies and structural castings.

Cast Aluminium Alloy Series & Principal Alloying Element

Alloy Series	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

Cast Aluminium Alloys Naming System

For cast alloys, the alloy numbering system follows a three-digit-plus-decimal format (e.g., 356.0). Here’s what it means:

First digit: Indicates the primary alloying element added to the aluminium (e.g., silicon, copper, magnesium).

Second and third digits: These are arbitrary numbers used to identify a specific alloy within that series.

Decimal point: The number after the decimal tells you if it’s a casting or ingot:

• .0: Indicates a final shape casting.
• .1 or .2: Indicates an ingot.

Capital letter prefix: Shows a modification of a specific alloy in the series.

For example, A356.0:

• A: Indicates a specific process or treatment applied to the base alloy 356.0
• 3: Silicon plus copper and/or magnesium alloy series
• 56: Identifies the alloy within the 3xx.x series
• .0: Indicates it’s a casting, not an ingot

This system helps classify cast alloys more specifically, identifying not only the alloy but also its modification and the form it takes.

Why Understanding These Alloys Matters

Choosing the right aluminium alloy can make a huge difference in your project’s success. Whether you’re building aircraft wings or designing kitchen appliances, understanding the characteristics of each alloy is essential. Each series offers different strengths, corrosion resistance and workability, making it easier to pick the perfect material.

For businesses looking to explore or trade aluminium alloys, AL Biz offers a comprehensive platform that connects aluminium suppliers with buyers, streamlining the process.

Conclusion

Aluminium alloys are classified into series based on the metals added to aluminium. Whether you’re looking for lightweight, corrosion-resistant materials or high-strength alloys, the 1xxx to 8xxx series offers a wide range of options. Knowing which alloy to choose can help ensure your project is both efficient and durable.

To find the right aluminium alloy for your needs, AL Biz provides a reliable platform where you can access a variety of materials and connect with trusted suppliers. Post your buying requirement or RFQ today!