Comparing Aluminium Alloys: Find the Right Material for Your Part
A practical guide to selecting aluminium alloys for CNC machining, sheet metal fabrication, and DMLS 3D printing
Aluminium is one of the most widely used metals in manufacturing – and for good reason. It offers an excellent combination of light weight, strength, corrosion resistance, and affordability. From automotive components and aerospace structures to consumer electronics and industrial machinery, aluminium alloys are found in almost every engineering sector. It is also the most commonly requested material at Konlida Precision Technology.
Choosing the right aluminium alloy is critical because different alloys have significantly different properties, which directly affect part performance, manufacturability, durability, and cost. This guide compares the most common aluminum alloys available through our CNC machining, sheet metal fabrication, and DMLS metal 3D printing services.
Why Aluminium?
Aluminium has a high strength‑to‑weight ratio – it is lightweight yet strong and flexible. It is also affordable, corrosion‑resistant, and works well across a wide range of applications. Most commonly, aluminium is alloyed with other elements such as silicon, magnesium, chromium, copper, zinc, and manganese.
Automotive Applications
Aluminium alloys are widely used in the automotive industry due to their versatility. The material's formability and corrosion resistance make it easy to work with and shape, while its structural soundness meets the requirements for vehicle bodies. Lightweighting helps reduce emissions and meet fuel economy standards. Common applications include structural components, suspension parts, engine blocks, and heat exchangers.
For more on automotive manufacturing, see our automotive industry solutions.
Aerospace Applications
Aluminum alloys are often the preferred material for aerospace designs due to their corrosion resistance and high strength‑to‑weight ratio. Compared to steel, aluminum is significantly lighter, allowing aircraft to either carry more payload or improve fuel efficiency. For example, a 20% weight reduction in a commercial aircraft can generate a 10–12% improvement in fuel efficiency. Common aerospace applications include fuel nozzles, heat exchangers, manifolds, turbo pumps, flow components, and fasteners.
For more on aerospace manufacturing, see our aerospace industry solutions.
How Aluminum Alloys Are Named
Aluminum alloys are designated by a four‑digit numerical code. The first digit represents the principal alloying element:
| Series | Principal Alloying Element |
|---|---|
| 1xxx | >99% aluminium (pure) |
| 2xxx | Copper |
| 3xxx | Manganese |
| 4xxx | Silicon |
| 5xxx | Magnesium |
| 6xxx | Magnesium and Silicon |
| 7xxx | Zinc |
The second digit indicates a modification of a specific alloy; the third and fourth digits are arbitrary numbers assigned to specific alloys in the series.
Common Aluminium Alloys – Comparison Table
| Material | Process | Tensile Strength (MPa) | Elongation | Hardness |
|---|---|---|---|---|
| 6061‑T651 | CNC Milling, CNC Turning, Sheet Metal | 276 | 17% | 95 HBW |
| 7075‑T651 | CNC Milling, CNC Turning | 572 | 11% | 85 HBW |
| 5052‑H32 | Sheet Metal | 228 | 12% | 60 HBW |
| 5754 | Sheet Metal (partner network) | 140–280 | ≥2% | ≥50 HRB |
| 2024 | CNC Milling, CNC Turning | 469 | 19% | 120 HRB |
| AlSi10Mg | DMLS (High Resolution, 20 µm) | 268 | 15% | 42 HRB |
| AlSi10Mg | DMLS (Normal Resolution, 30 µm) | 345 | 8% | 59 HRB |
| AlSi10Mg | DMLS (Large Format, 40 µm) | 296 | 10% | 50 HRB |
For detailed material data sheets, see our Materials Comparison Guide.
Alloy Profiles
Aluminum 6061 – The Versatile Workhorse
6061 is the most commonly used aluminium alloy at Konlida, available for CNC machining and sheet metal fabrication. It offers a balanced profile with good strength, excellent weldability, superior corrosion resistance, and good formability at a reasonable cost. It is generally selected where welding or brazing is required or for high corrosion resistance. Note that welding 6061 can weaken the heat‑affected zone, so post‑weld treatment may be needed.
Typical applications: Automotive parts, pipelines, marine gear, furniture, consumer electronics, structural components.
Aluminum 7075 – High Strength
7075 offers exceptional high strength‑to‑weight ratio, significantly exceeding that of 6061, making it ideal for high‑stress applications. However, this superior strength comes with trade‑offs: poor weldability, lower general corrosion resistance, susceptibility to stress corrosion cracking, higher cost, and lower ductility than 6061.
Typical applications: Aerospace structures, high‑performance sporting equipment, military components.
Aluminum 2024 – Aerospace Grade
2024 is a high‑strength alloy with good fatigue resistance, commonly used in aerospace applications. It is easily machined but has lower corrosion resistance than 6061 or 7075, and typically requires cladding (Alclad) for corrosion protection.
Typical applications: Aircraft structural parts, wing skins, fuselage frames.
Aluminum 5052 – Marine Grade
5052 is a magnesium‑based alloy with excellent corrosion resistance, particularly in marine environments. It is stronger than 6061 but less formable, and is not heat‑treatable.
Typical applications: Marine components, fuel tanks, sheet metal parts requiring good formability.
AlSi10Mg – For DMLS 3D Printing
AlSi10Mg is the aluminum alloy used in our DMLS metal 3D printing service. It is similar to a 3000‑series casting alloy, offering good strength, excellent thermal properties, and high corrosion resistance. Parts produced by DMLS typically have mechanical properties exceeding their die‑cast counterparts.
6061 vs. 7075 – Which Should You Choose?
| Attribute | 6061 | 7075 |
|---|---|---|
| Strength | Good | Excellent (≈2× stronger) |
| Weight | Light | Light |
| Corrosion resistance | Excellent | Moderate (susceptible to SCC) |
| Weldability | Good | Poor (fusion welding not recommended) |
| Formability | Good | Limited |
| Machinability | Excellent | Good (abrasive) |
| Cost | Lower | Higher (≈3×) |
| Typical use | General engineering, marine, automotive | Aerospace, high‑stress applications |
Recommendation: Choose 6061 for most general‑purpose applications where weldability, corrosion resistance, and cost are important. Choose 7075 when maximum strength‑to‑weight ratio is critical and welding is not required.
For help with material selection, contact our applications engineering team.
Finishing Options for Aluminium Parts
Konlida offers several finishing options for aluminum parts through our CNC machining and sheet metal services.
Anodising
Anodising is an electrochemical process that creates a durable, corrosion‑resistant oxide layer on the aluminum surface.
| Type | Description | Typical Use |
|---|---|---|
| Type I – Chromic Acid | Thin coating, grey appearance. Non‑conductive. | Welded parts, paint primer |
| Type II – Sulfuric Acid | Thicker, durable, dyeable in colours. Non‑conductive. | Consumer products, automotive parts, flashlights |
| Type III – Hard Anodise (Hardcoat) | Thickest, hardest coating (400–600 HV). Non‑conductive. | High‑wear applications, aerospace, defence |
Standard colours: Clear (Type II Class 1) and Black (Type II Class 2) are available with no added lead time. Custom colours (red, blue, etc.) add approximately 2 days.
Chromate Conversion Coating (Chem Film)
A thin, conductive coating that provides corrosion protection while maintaining electrical conductivity. Available in clear (RoHS compliant) and yellow (hexavalent chromium – non‑RoHS, restricted in EU).
Powder Coating
A tough, polymer‑based coloured finish applied electrostatically and cured at high temperature. Offers excellent durability and aesthetic appeal. Added lead time: approximately 5 days.
Plating (via Partner Network)
Electroless nickel, zinc, and other plating options are available through our partner network. These finishes add corrosion protection and wear resistance but increase lead time and cost.
Natural Passivation – Self‑Healing Oxide Layer
One of aluminium's most useful characteristics is its natural passivation. When exposed to air, aluminium forms a thin, transparent layer of aluminium oxide on its surface. This oxide layer acts as a barrier against further corrosion and will self‑repair if scratched – provided the surrounding environment contains oxygen.
Summary: Choosing the Right Aluminium Alloy
| If you need... | Choose... |
|---|---|
| The most versatile, balanced alloy for general use | 6061 |
| Maximum strength for high‑stress applications | 7075 |
| Aerospace‑grade strength with good fatigue resistance | 2024 |
| Excellent marine corrosion resistance | 5052 |
| Metal 3D printing with good thermal properties | AlSi10Mg (DMLS) |
There is no single “best” aluminium alloy – the right choice depends entirely on your part's functional requirements, environment, and production method. Our applications engineering team can help you evaluate trade‑offs and select the optimal material for your specific application.