COMPREHENSIVE TECHNICAL ANALYSIS AND DATASHEET OF ALUMINIUM 7075 FASTENERS
Aluminium 7075 (UNS A97075) represents the absolute pinnacle of high-strength aerospace metallurgy. By aggressively alloying the aluminium base with 5.1% to 7.1% Zinc (Zn), along with significant additions of Magnesium and Copper, this alloy achieves a massive response to thermal precipitation hardening. When subjected to the T6 temper process (solution heat-treated and artificially aged), 7075 develops an ultimate tensile strength that rivals—and often exceeds—that of many structural carbon steels, while weighing nearly three times less.
Because of its extreme strength-to-weight ratio, Aluminium 7075 is the undisputed material of choice for highly stressed structural applications where weight reduction is mission-critical. However, this immense strength comes with strict engineering trade-offs: 7075 is generally considered unweldable and possesses lower baseline corrosion resistance than the 6000 or 5000 series alloys. Therefore, 7075 fasteners are heavily utilized in their hard-coat anodized state for commercial aviation, military defense systems, and elite motorsport assemblies.
■ Product Overview & Specifications
| Material Classification | Precipitation-Hardening Zinc-Aluminium Alloy (Aerospace Grade) |
|---|---|
| UNS Designation | A97075 |
| Microstructure | FCC Matrix with MgZn₂ (Magnesium Zinc) Precipitates |
| Magnetic State | Completely Non-Magnetic |
| Density | 2.81 g/cm³ (0.102 lb/in³) |
| Size Range | Metric: M3 to M36 | Imperial: #4 to 1-1/2" |
| Primary Attribute | Ultimate Tensile Strength Rivaling Carbon Steel |
■ Proprietary Datasheet Download (GATED)
Aluminium 7075-T6 Aerospace Alloy — Complete Technical Datasheet
Contains detailed maximum shear-stress thresholds for aircraft structural joints, MIL-A-8625 Type III Hardcoat Anodizing thread tolerances, and critical fracture toughness limits.
⬇ DOWNLOAD DATASHEET■ MTC Integration Section
In aerospace and tactical defense manufacturing, structural failure at altitude or under ballistic stress is catastrophic. Verification of the exact T6 thermal aging profile and Zinc stoichiometry is absolutely mandatory. Ananka provides total, aerospace-grade mill traceability.
- EN 10204 Type 3.1: Validates the critical Zinc, Magnesium, and Copper loading required for precipitation hardening, and certifies the physical Brinell hardness needed to confirm the T6 thermal temper.
- EN 10204 Type 3.2: Available upon request for commercial aviation, military tactical vehicles, and UAV airframe construction requiring strict AMS (Aerospace Material Specification) compliance and third-party testing oversight.
■ Chemical Composition
The phenomenal strength of 7075 relies heavily on Zinc as its primary alloying element. When combined with Magnesium, it forms MgZn₂ precipitates during the artificial aging process. A deliberate addition of Copper further increases structural strength, while Chromium serves as a grain-refiner to improve resistance to stress-corrosion cracking.
| Aluminium (Al) | Zinc (Zn) | Magnesium (Mg) | Copper (Cu) | Chromium (Cr) | Iron (Fe) |
|---|---|---|---|---|---|
| Balance (~90.0) | 5.10 – 7.10 | 2.10 – 2.90 | 1.20 – 2.00 | 0.18 – 0.28 | 0.50 Max |
■ Mechanical Properties
| Mechanical Property | Typical Limits (T6 Heat-Treated Temper) |
|---|---|
| Tensile Strength | 74,000 - 83,000 psi (510 - 572 MPa) |
| Yield Strength | 63,000 - 73,000 psi (434 - 503 MPa) |
| Elongation (in 2 inches) | ~ 11% |
| Hardness (Brinell) | 150 HB |
■ Equivalent Grades & Designations
| Standard / System | Designation |
|---|---|
| ASTM Specifications | ASTM B211 (Bar, Rod, Wire), ASTM F468 (Fasteners) |
| Common Trade Names | 7075-T6, Zicral, Ergal, Fortal Constructal |
| European Equivalent | EN AW-7075 / AlZn5.5MgCu (DIN 3.4365) |
| Military / Aerospace | AMS 4122, QQ-A-225/9 |
■ Applications & Industries
- Aerospace & Aviation: Primary structural bolts for commercial aircraft wings, fuselage bulkheads, and military fighter jet airframes where steel is too heavy.
- Tactical & Defense Firearms: Mil-spec receiver pins, customized assembly screws, and structural retaining hardware for M16/AR-15 rifle platforms requiring rigid, lightweight performance.
- Extreme Sports & Motorsports: High-stress retaining bolts for professional rock-climbing carabiners, downhill mountain bike suspension linkages, and Formula 1 chassis hardware.
■ Compatible Fastener Assemblies
| Mating Bolts/Studs | Internal Threads (Nuts) | Washers |
|---|---|---|
| 7075-T6 Hex Bolts & Socket Caps | 7075-T6 Precision Hex Nuts | 7075-T6 Flat Washers |
■ Torque & Installation Guidelines
Due to its extreme yield strength, 7075-T6 can withstand torque loads far exceeding any other aluminium alloy. However, because it is heavily alloyed with Zinc and Copper, it is highly prone to severe thread galling and galvanic seizing. Aerospace-grade dialectric anti-seize or dry-film Molybdenum lubricants are mandatory prior to torquing.
| Nominal Diameter | Threads Per Inch (UNC) | Max Target Torque (in-lbs) | Max Target Torque (ft-lbs) |
|---|---|---|---|
| 1/4" | 20 | 90 - 100 | ~ 8.0 |
| 5/16" | 18 | 175 - 195 | ~ 15.5 |
| 3/8" | 16 | 300 - 330 | ~ 26.0 |
| 1/2" | 13 | 650 - 700 | ~ 56.0 |
■ Frequently Asked Questions
1. Why choose 7075 over the 6061 workhorse alloy?
It is a choice between raw strength and versatility. Aluminium 7075 is nearly twice as strong as 6061-T6, boasting a tensile yield comparable to many steels. If your application is weight-critical and undergoes massive structural stress (like an aircraft wing or a tactical rifle receiver), 7075 is the only choice. However, 6061 is much cheaper, easily weldable, and far more corrosion-resistant.
2. Can Aluminium 7075 fasteners be welded?
No. Within the engineering community, 7075 is universally classified as non-weldable. The high concentration of Zinc and Copper makes the alloy incredibly prone to "micro-cracking" and catastrophic porosity during the rapid cooling phase of welding. Furthermore, the intense heat of a welding torch completely destroys the T6 temper, ruining the metal's strength. 7075 must be used strictly for mechanical joints.
3. Why are 7075 parts almost always anodized?
Because 7075 is heavily alloyed with Zinc and Copper, it lacks the stable, natural oxide layer found in pure aluminium (like 1100) or magnesium-aluminium (like 5052). In wet or marine environments, 7075 is highly susceptible to galvanic corrosion and exfoliation. To protect this valuable structural integrity, the fasteners are subjected to Type II or Type III (Hardcoat) anodizing, which chemically builds a hard, protective sapphire-like shell over the metal.
