Aluminum Material Comparison

Q: Can 7075 aluminum be cast?

No. 7075 is a wrought alloy. Use A356-T6, A319, or 535 for high-strength castings.

Q: What is the cheapest aluminum alloy?

ADC12 for die casting; 6061-T6 for CNC machining applications.

Q: Which aluminum alloy has the best corrosion resistance?

6061-T6 offers excellent corrosion resistance; 7075 requires coating in harsh environments.

Q: How do I choose between 6061 and 7075 for CNC?

Use 7075 only when yield strength above ~400 MPa is required; 6061-T6 is sufficient for most structural parts at lower cost.

Why Material Selection Matters

Choosing the right aluminum material for casting or machining is critical for mechanical performance, total cost, and manufacturability. Alloy chemistry directly controls yield strength, elongation, corrosion resistance, and how a part responds to heat treatment or secondary operations. Selecting an over-spec alloy such as 7075 when 6061 suffices can increase raw material cost by 40–60% with no functional benefit.

Wrong material choices also drive scrap, rework, and tooling changes. A wrought alloy specified for a die casting application may not fill thin walls; a casting alloy machined from billet wastes material and cycle time. This guide compares 6061-T6, 7075-T6, ADC12, and A356-T6 so engineers can align alloy, process, and budget before committing to production tooling.

aluminum alloy comparison chart, 6061 7075 ADC12 properties, industrial infographic

Technical Deep-Dive: Each Alloy

6061-T6

Composition: Al 95.8–98.6%, Mg 0.8–1.2%, Si 0.4–0.8%. Yield 276 MPa, tensile 310 MPa, elongation 12–17%, hardness ~95 HB. Excellent weldability and corrosion resistance; heat treatable to T6. Best for structural CNC parts, marine fittings, and general automotive components where machinability and cost balance matter.

7075-T6

Composition: Al 87.1–91.4%, Zn 5.1–6.1%, Mg 2.1–2.9%, Cu 1.2–2.0%. Yield 503 MPa, tensile 572 MPa, elongation ~11%, hardness ~150 HB. Highest strength among common wrought aluminums; fair weldability; stress-corrosion risk in certain environments without coating. Used for aerospace structural parts and high-stress tooling machined from billet.

ADC12

Composition: Al 76–81%, Si 9.6–12%, Cu 1.5–3.5%. Tensile ~310 MPa, elongation 2–3%, hardness 95–110 HB. Formulated for die casting with excellent fluidity; not effectively heat treatable for ductility gains. Ideal for automotive blocks, housings, and consumer electronics at high volume.

A356-T6

Casting alloy with tensile 262 MPa (T6), elongation 5–10%, hardness 80–90 HB. Excellent castability for gravity and sand casting of complex geometries. Lower cost than machining from 6061 billet for medium-complexity cast parts requiring heat treatment.

Property	6061	7075
Strength	Medium	Very High
Machinability	Excellent	Good
Corrosion Resistance	Excellent	Moderate
Cost	Lower	Higher
Applications	General parts	Aerospace

Property	6061	ADC12
Process	CNC Machining	Die Casting
Strength	Medium	Medium
Surface Finish	High	Good
Cost	Higher	Lower (volume)
Best Use	Precision parts	Mass production

7075 vs ADC12

Property	7075	ADC12
Strength	Very High	Medium
Manufacturing	CNC	Casting
Cost	High	Low
Applications	Aerospace	Automotive

high strength aluminum vs casting aluminum comparison, industrial detail

Complete Property Comparison

Property	6061-T6	7075-T6	ADC12	A356-T6
Yield Strength (MPa)	276	503	160	207
Ultimate Tensile (MPa)	310	572	310	262
Elongation (%)	12–17	11	2–3	5–10
Hardness (HB)	95	150	95–110	80–90
Machinability	Excellent (90%)	Good (70%)	Fair	Good
Corrosion Resistance	Excellent	Moderate	Good	Good
Weldability	Excellent	Fair	Poor	Good
Heat Treatable	Yes (T6)	Yes (T6)	No	Yes (T6)
Typical Cost	$$	$$$$	$	$$
Best Process	CNC / Casting	CNC	Die Casting	Gravity / Sand

detailed aluminum alloy property comparison chart, mechanical values

Process-Specific Material Recommendations

CNC machining: 6061-T6 is the most cost-effective default for general structural parts; specify 7075-T6 only when yield strength above 450 MPa is required and budget allows.

Die casting: ADC12 is the industry standard for high-volume thin-wall parts. 7075 is not castable in conventional HPDC — use ADC12 or A380 instead.

Gravity casting: A356-T6 is ideal for permanent mold parts needing heat treatment and moderate elongation. 6061 can be cast with careful parameter control but is not preferred.

Sand casting: A356, A319, and 535 alloys offer the best combination of fluidity, strength after T6, and tooling economy for prototypes and low-to-medium volumes.

engineer comparing aluminum materials chart, selecting best option, industrial workspace

Real-World Selection Scenarios

Automotive Bracket

ADC12 die cast, 5,000+ pcs/year. Chosen for lowest per-part cost and acceptable strength in a non-critical mounting bracket. Post-cast machining limited to critical bores only.

Aerospace Mount

7075-T6 CNC from billet, ~200 pcs/year. Strength-critical interface; machining cost acceptable at low volume where die casting tooling cannot be justified.

Marine Fitting

6061-T6 machined and anodized, 500–1,000 pcs/year. Corrosion resistance priority; 7075 avoided due to SCC risk in saltwater without hard anodize.

Application-Based Recommendations

Automotive

ADC12 or 6061 depending on volume.

Aerospace

7075 for strength.

Electronics

6061 for machining and finishing.

Industrial Equipment

industrial aluminum parts, machinery components, versatile applications

6061 for versatility.

Common Mistakes in Material Selection

Choosing Over-Spec Materials

Using 7075 when 6061 is sufficient increases cost.

Ignoring Manufacturing Process

Not all materials are suitable for casting or machining.

Focusing Only on Cost

Low-cost materials may reduce performance.

Frequently Asked Questions

Can 7075 aluminum be cast?

No. 7075 is a wrought alloy optimized for machining from billet. For high-strength castings, use A356-T6, A319, or 535 alloys in sand or gravity processes.

What is the cheapest aluminum alloy?

ADC12 offers the lowest per-part cost in high-volume die casting. For CNC machining, 6061-T6 billet is typically the most economical structural alloy.

Which aluminum alloy has the best corrosion resistance?

6061-T6 provides excellent marine-grade corrosion resistance. 7075 requires protective coating in aggressive environments due to copper content.

How do I choose between 6061 and 7075 for CNC?

Specify 7075 only when yield strength above ~400 MPa is required. For most brackets, housings, and fixtures, 6061-T6 delivers adequate strength at 30–50% lower material cost with better machinability.

6061 vs 7075 vs ADC12 — Which One Should You Choose?