7075-T6 temper
60% of brass
W/mK
lb/in³
What Is Aluminum 7075-T6?
Aluminum 7075-T6 is the strongest common aluminum alloy. It has a tensile strength of 83 ksi — about 2x stronger than 6061-T6. Engineers choose it when a part needs to be light and strong at the same time.
The "7075" refers to the alloy. It contains zinc as its main alloying element, plus magnesium and copper. These give it very high strength but make it harder to weld. The "T6" temper means it was heat treated and aged for peak strength.
7075-T6 is called "aerospace aluminum" because it is the go-to material for aircraft structures. Wing spars, fuselage frames, and landing gear components are all made from 7075. But it is not just for planes. Any part that needs high strength at low weight — like gears, high-stress brackets, and defense components — benefits from 7075-T6.
Aluminum 7075-T6 Material Properties
Here are the key properties of 7075-T6 and why each one matters for your parts.
| Property | Value | Why It Matters |
|---|---|---|
| Tensile Strength | 83 ksi (572 MPa) | Stronger than most steels by weight. For high-load structural parts. |
| Yield Strength | 73 ksi (503 MPa) | Very high. Parts hold shape under heavy loads without permanent bending. |
| Elongation | 11% | Slightly less ductile than 6061 (12%). Still bends before breaking. |
| Hardness | Brinell 150 / Rockwell B87 | Very hard for aluminum. Resists dents and wear. Holds tolerances well. |
| Thermal Conductivity | 130 W/mK | Good heat transfer, but 22% less than 6061. Use 6061 for heat sinks. |
| Density | 0.102 lb/in³ (2.81 g/cm³) | Only 4% heavier than 6061. Still 1/3 the weight of steel. |
| Machinability | Fair — 60% of brass | Harder to cut than 6061 but still machines well. Slightly longer cycle times. |
| Corrosion Resistance | Fair | Less corrosion resistant than 6061. Needs anodizing or coating for outdoor use. |
| Weldability | Poor | Prone to hot cracking. Use bolts, rivets, or adhesive to join 7075 parts. |
| Anodizing | Good | Anodizes well but colors come out slightly darker than 6061. Works for functional finishes. |
Common 7075 Tempers
The temper changes how strong and workable the aluminum is. Here are the 7075 tempers you will see most often.
| Temper | Tensile Strength | Yield Strength | Best For |
|---|---|---|---|
| 7075-T6 | 83 ksi | 73 ksi | Most CNC parts. Peak strength. Default for aerospace brackets, gears, structural parts. |
| 7075-T651 | 83 ksi | 73 ksi | Same strength as T6, but stress-relieved by stretching. Better for large plate parts that need to stay flat after machining. |
| 7075-T7351 | 68 ksi | 58 ksi | Overaged temper. 18% less strong than T6, but much better resistance to stress corrosion cracking. Used in thick sections for aerospace. |
| 7075-O | 33 ksi | 15 ksi | Fully annealed (soft). Used for forming and bending before heat treatment. Not for structural use in this condition. |
Which temper should you pick? Use 7075-T6 for most parts. Use 7075-T651 for large flat plates over 6 inches to reduce warping. Use 7075-T7351 if stress corrosion cracking is a concern — common in thick aerospace forgings.
Aluminum 7075 vs Other Materials
How does 7075-T6 stack up against other popular CNC materials? This table shows the key differences.
| Property | 7075-T6 | 6061-T6 | Ti-6Al-4V | Steel 4140 |
|---|---|---|---|---|
| Tensile Strength | 83 ksi | 45 ksi | 130 ksi | 95 ksi |
| Density | 0.102 lb/in³ | 0.098 lb/in³ | 0.160 lb/in³ | 0.284 lb/in³ |
| Strength-to-Weight | Excellent | Good | Excellent | Fair |
| Machinability | Fair (60%) | Good (70%) | Poor (22%) | Fair (55%) |
| Cost per Part | $85–$400 | $65–$300 | $250–$800+ | $100–$350 |
| Corrosion Resistance | Fair | Good | Excellent | Poor (needs coating) |
| Weldable | No | Yes | Yes (inert gas) | Yes |
| Best For | High-stress, light parts | General purpose | Extreme strength + corrosion | Heavy-duty, heat-treated parts |
Bottom line: 7075-T6 gives you steel-level strength at 1/3 the weight. It costs less than titanium Ti-6Al-4V and machines faster. Use it when 6061 is not strong enough but titanium is overkill.
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Upload CAD for Instant QuoteIndustries and Applications
Aluminum 7075-T6 shines where strength and weight matter most. Here are the industries and parts where we machine it.
Aerospace
Wing spars, fuselage frames, bulkheads, fittings, and brackets. 7075-T6 meets AMS 4078 (plate) and AMS 4045 (sheet). The standard material for aircraft structures since the 1940s.
Defense
Weapon system housings, armor mounting brackets, UAV structural parts, and mil-spec hardware. High strength at low weight is critical when every ounce matters in the field.
Automotive & Motorsport
Suspension components, uprights, bell cranks, and gearbox housings. Race teams use 7075-T6 where 6061 is not strong enough and steel is too heavy.
Robotics & Automation
High-load arm links, joint brackets, and structural plates. When a robot arm lifts heavy payloads, 7075-T6 keeps the arm light and stiff.
Industrial Equipment
Gears, cams, high-load fixtures, and tooling plates. 7075-T6 hardness (Brinell 150) resists wear in demanding environments.
Hardware Startups
Structural prototypes that need to survive stress testing. Use 7075-T6 to test at real loads without building in steel. Iterate fast with 3-day delivery.
Design Tips for Machining Aluminum 7075
7075 machines well but is harder than 6061. These tips help you get the best parts at the lowest cost.
- Add inside corner radii of 0.030" or larger. Same as 6061 — end mills are round. Sharp inside corners need slow EDM passes that cost 3–5x more.
- Keep walls at 0.050" thick or more. 7075 is stiffer than 6061, so thin walls deflect less. But walls under 0.050" still cause chatter. Stay at 0.060"+ for best results.
- Plan for stress relief. 7075 has high internal stresses. Large parts (over 8 inches) may warp after machining. Use T651 stock and rough-cut, stress relieve, then finish-cut for flat results.
- Avoid welding designs. 7075 cannot be welded easily. Design parts to be bolted, riveted, or bonded instead. If you need weldable aluminum, switch to 6061-T6.
- Use standard drill and tap sizes. Sizes like 1/8", 3/16", 1/4" and taps like 4-40, 6-32, 8-32, 10-32, 1/4-20 cost less than non-standard sizes.
- Limit pocket depth to 4x width. Deep pockets in 7075 need long, thin tools. The higher hardness causes more tool deflection. Keep depth under 4:1 for clean finishes.
- Specify corrosion protection. 7075 has fair corrosion resistance — worse than 6061. Anodizing or chromate conversion is recommended for any part exposed to moisture.
Surface Finishes for Aluminum 7075
7075 takes functional finishes well. Colors come out slightly darker than 6061 due to the zinc content.
- As-machined (125 Ra): Clean tool marks visible. Ready for internal parts, test fixtures, and prototypes. No extra cost.
- Bead blasted: Uniform matte texture. Hides tool marks. Good for non-cosmetic housings and brackets.
- Type II anodizing: Hard oxide layer in clear, black, or colors. Colors run slightly darker and more yellow-green than 6061. Good for functional corrosion protection.
- Type III hard anodizing: Thicker oxide layer (0.001–0.002 inches). Very hard at 60–70 Rockwell C. Excellent for high-wear aerospace parts.
- Chromate conversion (Alodine): Thin chemical coating per MIL-DTL-5541. Gold or clear. The go-to aerospace finish for 7075. Adds corrosion resistance while keeping electrical conductivity.
- Powder coat: Durable paint finish in any RAL color. Good for outdoor or cosmetic parts. Thicker than anodizing at 0.002–0.006 inches.
- Dry film lubricant: PTFE or MoS2 coating per MIL-PRF-46010. Reduces friction on sliding surfaces. Common on aerospace 7075 parts.
- Tumble/deburr: Removes sharp edges. Safe to handle. Standard on all parts unless noted otherwise.
Tolerances for Aluminum 7075 CNC Parts
7075 holds tolerances very well because of its high hardness (Brinell 150). It springs back less during cutting than softer alloys.
| Tolerance Level | Value | Use Case |
|---|---|---|
| Standard | ±0.005" (±0.127 mm) | General features, non-critical dimensions, clearance holes. |
| Precision | ±0.001" (±0.025 mm) | Bearing fits, mating surfaces, alignment pins, dowel holes. |
| Critical | ±0.0005" (±0.013 mm) | Aerospace fits, optical mounts, sealing surfaces. Requires CMM inspection. |
Surface finish tolerances: As-machined is 125 Ra or better. We can hold 32 Ra or 16 Ra on request. Ground surfaces hold flatness of 0.001" per inch.
Stress Relief for Large 7075 Parts
Aluminum 7075 has high residual stress in the raw stock. When you machine away material, the remaining stress can cause the part to warp. This matters most on large, thin parts — anything over 8 inches with walls under 0.25".
We handle this by using T651 stress-relieved plate, roughing first with 0.030" stock left, letting the part relax, then finish-machining to final dimensions. This adds 1–2 days but keeps your part flat. Let us know if flatness is critical and we will plan for it.
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