Engineering Guide — Aluminum Alloys
Aluminum Material Properties: Engineering Guide
Understanding aluminum material properties is essential for choosing the right alloy and manufacturing process. Aluminum offers a rare combination of low density, good corrosion resistance, and excellent machinability, making it one of the most widely used metals in engineering.
At Baetro, we help customers turn aluminum material knowledge into precision parts through aluminum CNC machining, sheet metal, and finishing services. Upload your CAD file for an instant quote on machined aluminum parts in under 60 seconds.
2.7 g/cm³
Density
6061 / 7075
Most common alloys
≥ 85%
Machinability rating
0.5–1.5%
Shrinkage (casting)
Aluminum Material Guide
What Is Aluminum?
Aluminum is a lightweight, silvery-white metal with excellent thermal and electrical conductivity. Pure aluminum is relatively soft, so most engineering applications use aluminum alloys that are strengthened by adding elements such as copper, magnesium, silicon, manganese, or zinc.
Understanding aluminum material properties starts with distinguishing between pure aluminum and the alloy families used in manufacturing.
Pure Aluminum (1xxx series)
Excellent corrosion resistance and electrical conductivity, but low strength — suited for non-structural applications.
Wrought vs Cast Alloys
Wrought alloys (2xxx–7xxx) are mechanically worked; cast alloys (Axxx) are poured into molds. Each has distinct properties.
Heat-Treatable Grades
2xxx, 6xxx, and 7xxx series can be strengthened via heat treatment (T6, T7 tempers) for higher strength-to-weight ratios.
Non-Heat-Treatable Grades
3xxx, 4xxx, and 5xxx series rely on work hardening (strain hardening) for strength — excellent for forming and welding.
Aluminum Series Overview
1xxx (pure) · 2xxx (copper) · 3xxx (manganese) · 4xxx (silicon) · 5xxx (magnesium) · 6xxx (magnesium-silicon) · 7xxx (zinc) — each with distinct properties for specific applications.
Aluminum Alloy Guide
Common Aluminum Alloys Compared
Choosing the right alloy means matching aluminum material properties to the demands of the application. Below are the most common alloys used in machined and fabricated parts.
6xxx Series
6061 Aluminum
6061-T6 is the most widely used aluminum alloy for CNC machining. Offers good strength, excellent corrosion resistance, and outstanding machinability. Weldable and easily anodized.
- Best for: structural frames, brackets, enclosures, automotive parts
- Machinability: Excellent · Weldability: Good
- Typical temper: T6 (solution heat-treated + aged)
7xxx Series
7075 Aluminum
7075-T6 is one of the strongest commercial aluminum alloys. Its high strength-to-weight ratio makes it popular in aerospace and high-performance applications. Harder to machine than 6061, with lower corrosion resistance.
- Best for: aerospace, defense, high-stress structural parts
- Machinability: Moderate · Weldability: Poor
- Typical temper: T6, T73 (stress-corrosion resistant)
5xxx Series
5052 Aluminum
5052-H32 offers excellent corrosion resistance — especially in marine environments — and good formability. A top choice for sheet metal work including enclosures, panels, and brackets. Weldable and takes finishes well.
- Best for: marine components, enclosures, panels, brackets
- Machinability: Moderate · Weldability: Excellent
- Typical temper: H32 (strain-hardened + stabilized)
2xxx Series
2024 Aluminum
2024-T3 is a high-strength 2xxx alloy used primarily in aerospace. Offers good fatigue resistance and high strength but poor corrosion resistance — often clad with pure aluminum for protection.
- Best for: aerospace structures, high-fatigue applications
- Machinability: Good · Weldability: Poor
- Typical temper: T3 (solution heat-treated + cold-worked)
6xxx Series
6063 & 6082 Aluminum
Extrusion-friendly alloys with good corrosion resistance and moderate strength. Commonly used for architectural profiles, heat sinks, frames, and structural tubing. After extrusion, these profiles can be machined to tight tolerances.
- Best for: architectural profiles, heat sinks, frames
- 6063: Excellent formability · 6082: Higher strength
- Process: Extrusion + secondary CNC machining
Cast Tooling Plate
MIC-6 Aluminum
Cast aluminum tooling plate designed for excellent dimensional stability and flatness. Often used for fixtures, jigs, vacuum chucks, and precision base plates. Not as strong as 6061 or 7075, but invaluable for tooling applications.
- Best for: fixtures, jigs, vacuum chucks, base plates
- Key property: Exceptional flatness and stability
- Machinability: Good · Typical thickness: 6–100 mm
Surface Engineering
Aluminum Surface Finishes
Surface finishing can improve corrosion resistance, appearance, wear properties, and electrical insulation. The right finish depends on the operating environment, aesthetic requirements, and functional needs of the part.
Anodizing (Type II)
An electrochemical process that thickens the natural oxide layer for decorative and protective applications. Available in clear, black, and a wide range of colors. Adds durability and a premium appearance.
Hardcoat Anodizing (Type III)
Thicker, denser oxide layer for wear resistance and hardness. Provides superior abrasion resistance (comparable to hard chrome) and excellent electrical insulation. Ideal for sliding surfaces and high-wear components.
Powder Coating
A dry paint process that provides thick, durable, colored coatings. Excellent corrosion resistance and impact resistance. Wide range of colors and textures available for both functional and decorative applications.
Bead Blasting
Creates a uniform matte, satin, or textured finish by propelling fine glass or ceramic beads at the surface. Effectively reduces visible machining marks and provides an even aesthetic appearance.
Plating (Nickel, Zinc, Chrome)
Electroplated metal coatings that improve wear resistance, conductivity, or corrosion protection. Nickel and chrome provide a bright, decorative finish; zinc offers galvanic protection for steel substrates.
Chromate Conversion
A chemical film that improves corrosion resistance and paint adhesion without adding significant thickness. Clear (yellow) or clear (blue) finishes. Often used as a primer before powder coating or painting.
Need help choosing the right finish?
Anodizing services are available for all aluminum alloys. Contact our engineering team to discuss your application requirements, operating environment, and aesthetic goals — we'll recommend the optimal finish for your parts.
Machining Guide
Aluminum Machinability
Aluminum is one of the easiest metals to machine, but machinability varies by alloy. Understanding aluminum material properties helps you select the right alloy and cutting parameters.
General Machinability
Most aluminum alloys produce manageable chips, allow high cutting speeds, and deliver good surface finishes. The material is thermally conductive, which helps carry heat away from the cutting zone. However, aluminum can be gummy, causing chip buildup on tools if speeds and feeds are not optimized.
Alloy‑Specific Machining Considerations
6061: Excellent machinability. Produces fine chips and a good surface finish. Ideal for high-volume CNC production.
7075: Harder and more abrasive. Requires rigid setups, carbide tooling, and optimized coolant to prevent tool wear.
5052: More ductile and prone to burr formation. Often used for sheet metal rather than precision machining.
2024: Good machinability but can produce long chips. Careful chip control is important.
MIC‑6: Stable and machinable, primarily used for flat tooling plates and fixtures.
Tooling & Cutting Parameters
Carbide end mills are recommended for most aluminum machining. High spindle speeds and feed rates are typical due to aluminum's softness and thermal conductivity. Flood coolant or mist coolant helps prevent chip welding and improves surface finish.
Our engineers review every CAD file to recommend tooling and fixturing strategies that maximize quality and reduce cycle time.
Alloy
6061 Aluminum
Excellent machinability — fine chips, good surface finish. Ideal for high-volume production and general-purpose parts.
Alloy
7075 Aluminum
Harder and more abrasive — requires carbide tooling, rigid setups, and optimized coolant to manage tool wear.
Alloy
5052 Aluminum
Ductile and prone to burrs — better suited for sheet metal forming and fabrication rather than precision machining.
Alloy
MIC-6 Aluminum
Stable cast tooling plate — excellent flatness and dimensional stability for fixtures, jigs, and base plates.
Need help selecting the right aluminum alloy?
Upload your CAD file and our engineers will review your design, recommend the optimal alloy, and suggest cutting parameters for your specific geometry and quantity.
Alloy Guide
Aluminum Alloy Series Overview
The 6xxx and 7xxx series are the most common choices for machined aluminum parts because they offer an excellent balance of strength, machinability, and cost.
| Series | Main Alloying Element | Typical Characteristics |
|---|---|---|
| 1xxx | Pure aluminum (>99%) | Soft, excellent corrosion resistance, high conductivity |
| 2xxx | Copper | High strength, aerospace use, lower corrosion resistance |
| 3xxx | Manganese | Medium strength, good formability, often used in sheet |
| 4xxx | Silicon | Lower melting point, used in welding wire and castings |
| 5xxx | Magnesium | Good corrosion resistance, weldability, marine applications |
| 6xxx | Magnesium + Silicon | Versatile, machinable, weldable, heat treatable |
| 7xxx | Zinc | Highest strength, aerospace and high-performance parts |
The 6xxx and 7xxx series are the most common choices for machined aluminum parts because they offer an excellent balance of strength, machinability, and cost. Not sure which alloy fits your application? Upload your CAD file and our engineers will recommend the optimal series for your design.
Material Data
Key Aluminum Material Properties
The value of aluminum in engineering comes from a set of physical, mechanical, and chemical properties that can be tuned through alloying and heat treatment.
Mechanical Properties
| Alloy / Temper | Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|---|
| 6061-T6 | ~310 MPa (45 ksi) | ~276 MPa (40 ksi) | ~17% | ~95 HB |
| 7075-T6 | ~570 MPa (83 ksi) | ~503 MPa (73 ksi) | ~11% | ~150 HB |
| 5052-H32 | ~228 MPa (33 ksi) | ~193 MPa (28 ksi) | ~12% | ~60 HB |
| 2024-T3 | ~469 MPa (68 ksi) | ~324 MPa (47 ksi) | ~19% | ~120 HB |
| 6063-T5 | ~186 MPa (27 ksi) | ~145 MPa (21 ksi) | ~12% | ~55 HB |
| MIC-6 | ~165 MPa (24 ksi) | ~110 MPa (16 ksi) | ~3% | ~65 HB |
Values are approximate and can vary by supplier, orientation, and test method. Always verify properties against the material certificate for critical applications.
Key Design Considerations
- Corrosion Resistance: Aluminum naturally forms a thin oxide layer (Al₂O₃) that protects against further oxidation. Anodizing thickens this layer for additional protection and decorative color.
- Thermal Expansion: Coefficient of thermal expansion is ~23 µm/m·K — about double that of steel. Account for this difference when aluminum parts are assembled with steel fasteners or frames.
- Thermal & Electrical Conductivity: Aluminum conducts heat and electricity efficiently, making it ideal for heat sinks, bus bars, and electrical housings.
- Alloy Selection: 6xxx and 7xxx series are the most common choices for machined parts. Marine and chemical applications often use 5xxx or 6xxx alloys for superior corrosion performance.
- Reflectivity: Up to 92% for visible light and 98% for infrared — useful for reflectors and lighting applications.
Material Selection
Aluminum vs Steel: When to Choose Aluminum
Engineers often compare aluminum and steel when selecting a structural material. The right choice depends on weight, strength, corrosion resistance, cost, and manufacturing requirements.
Aluminum vs Steel
- Density: Aluminum ~2.7 g/cm³ · Steel ~7.8 g/cm³
- Strength-to-weight ratio: Aluminum — High · Steel — Moderate
- Corrosion resistance: Aluminum — Excellent (forms protective oxide) · Steel — Requires coating or stainless grades
- Machinability: Aluminum — Excellent, especially 6061 · Steel — Good to moderate, depending on grade
- Weldability: Aluminum — Good for 5xxx and 6xxx alloys · Steel — Excellent for mild steel
- Cost per unit weight: Aluminum — Higher · Steel — Lower
- Cost per unit stiffness: Aluminum — Higher · Steel — Lower
When to Choose Aluminum
Choose aluminum when weight savings, corrosion resistance, or thermal conductivity are priorities.
- Weight-critical applications: aerospace, automotive, portable products
- Corrosive environments: marine, chemical, outdoor exposure
- Thermal management: heat sinks, enclosures for electronics
- High machinability: complex geometries, rapid prototyping, production runs
Choose steel when maximum stiffness, wear resistance, or lowest raw material cost are more important.
Applications
Applications of Aluminum
Aluminum's combination of low weight, good strength, and corrosion resistance makes it suitable for a wide range of industries. Selecting the right alloy means balancing mechanical requirements, manufacturability, corrosion resistance, and cost.
Industry
Aerospace
Aircraft structures, brackets, fittings, and housings often use 7075, 2024, and 6061 alloys. Weight reduction is critical in aerospace, where aluminum has been a standard material for decades.
Industry
Automotive
Engine components, transmission housings, brackets, heat sinks, and chassis parts use aluminum to reduce vehicle weight and improve fuel efficiency. Automotive parts manufacturing benefits from aluminum's machinability and recyclability.
Industry
Electronics
Heat sinks, enclosures, bezels, and mounting brackets are commonly machined from 6061 aluminum. The material's thermal conductivity helps dissipate heat, while anodizing provides insulation and color options.
Industry
Medical Devices
Aluminum is used in surgical instruments, equipment housings, and patient positioning devices where lightweight, sterilizable, and corrosion-resistant materials are required.
Industry
Marine
Boat hulls, decks, and hardware often use 5xxx alloys such as 5052 and 5083 because of their excellent resistance to saltwater corrosion.
Industry
Industrial Equipment
Machinery components, frames, guides, and structural supports benefit from aluminum's lightweight, corrosion resistance, and excellent machinability across a range of alloys.
Alloy Selection Guide
Aluminum Material Selection Guide
Selecting the right alloy means balancing mechanical requirements, manufacturability, corrosion resistance, and cost. Use the guidelines below as a starting point.
Choose 6061 Aluminum When…
- You need a versatile, machinable alloy for general-purpose parts.
- Corrosion resistance and weldability are important.
- You want a cost-effective option for prototypes and production.
- The part will be anodized.
Choose 7075 Aluminum When…
- Maximum strength-to-weight ratio is required.
- The application is structural, aerospace, or high-performance.
- Welding is not required.
- Higher material and machining costs are acceptable.
Choose 5052 Aluminum When…
- The part will be formed from sheet metal.
- Marine or chemical corrosion resistance is critical.
- Weldability is more important than machinability.
Material Properties
Physical Properties of Aluminum
Aluminum is immediately recognizable by its low density and silvery appearance. These key physical properties make it ideal for heat sinks, enclosures, reflectors, and lightweight structural components.
Density
~2.7 g/cm³ — roughly one-third that of steel, enabling significant weight savings in structural and portable applications.
Melting Point
~660°C (1,220°F) — relatively low compared to steel, which influences casting and welding processes.
Thermal Conductivity
~237 W/m·K for pure aluminum — excellent heat dissipation, making aluminum the material of choice for heat sinks and thermal management components.
Electrical Conductivity
~62% of copper by volume, but roughly double by weight — widely used in electrical bus bars, connectors, and power distribution applications.
Reflectivity
Up to 92% for visible light and 98% for infrared — ideal for reflectors, lighting fixtures, and optical components.
Color & Finish
Silvery-white with a naturally bright finish that can be enhanced through polishing, anodizing, or bead blasting for decorative and functional surfaces.
Get Started
Get Aluminum Parts Machined with Baetro
Baetro turns aluminum material properties knowledge into precision parts. Our aluminum CNC machining service covers 6061, 7075, 5052, and other alloys with tolerances to ±0.001 inch.
- Engineering-First Material Guidance Our engineers review every CAD upload and provide free DFM feedback. We help you choose the right alloy, temper, tolerances, and finish based on your application. Whether you need a lightweight bracket or a high-strength aerospace fitting, we recommend the material and process that deliver the best result.
- Transparent Pricing and Lead Times Our instant quote tool shows price and lead time in under 60 seconds. There are no hidden setup fees, and we ship aluminum machined parts in 3–7 days with no minimum order quantity.
- Quality Assurance Every order ships from our ISO 9001 certified Qingdao facility with documented process controls. We provide dimensional inspection reports, material certificates, and full traceability for critical applications. For aerospace and medical projects, we can support AS9100 and ISO 13485 workflows.
FAQ
Frequently Asked Questions About Aluminum
Answers to common questions about aluminum properties, alloy selection, machinability, corrosion resistance, and lead times.
What are the main properties of aluminum?
Aluminum is lightweight, with a density of ~2.7 g/cm³. It has good corrosion resistance, high thermal and electrical conductivity, and can be alloyed to achieve a wide range of mechanical properties.
What is 6061 aluminum used for?
6061 aluminum is used for structural frames, brackets, enclosures, automotive parts, and general-purpose machined components. It is valued for its machinability, corrosion resistance, and weldability.
What is the difference between 6061 and 7075 aluminum?
7075 aluminum is significantly stronger than 6061 but is harder to machine, less corrosion resistant, and difficult to weld. 6061 is more versatile, cost-effective, and easier to finish.
Is aluminum corrosion resistant?
Yes. Aluminum forms a protective oxide layer that prevents further oxidation. Anodizing can increase this protection for harsh environments.
What is the density of aluminum?
Pure aluminum has a density of approximately 2.7 g/cm³, about one-third that of steel.
Can aluminum be welded?
Many aluminum alloys, including 6061 and 5052, can be welded. 7075 is generally considered poor for welding due to cracking and strength loss in the heat-affected zone.
What finishes can be applied to aluminum parts?
Common finishes include anodizing, powder coating, bead blasting, plating, and chromate conversion.
How fast can Baetro machine aluminum parts?
Baetro ships standard aluminum machined parts in 3–7 days. Expedited options are available for urgent prototypes.
Aluminum CNC Services
Start Your Aluminum Project with Baetro
Understanding aluminum material properties is the first step toward a successful part. Whether you need the versatility of 6061, the strength of 7075, or the formability of 5052, Baetro can machine and finish your aluminum parts with precision and speed.
Upload your CAD file today for an instant quote in under 60 seconds — with free DFM feedback, transparent pricing, and no minimum order quantity. Our engineers will help you select the right alloy, temper, and finish for your specific application.
Parts ship in 3–7 days · ISO 9001 & AS9100 certified · Full material traceability
Not ready to upload a file? Contact our engineers to discuss your project, review alloy options, or get guidance on tolerance and finish selection.