7085 aluminum plate
When you think of aluminum alloys, names like 6061 and 7075 might immediately come to mind, thanks to their widespread use and decades of proven performance. However, nestled in the family of 7xxx series aluminum alloys is the 7085 aluminum plate — a material that embodies the cutting edge of strength, toughness, and machinability.
What Makes 7085 Aluminum Plate Stand Out?
At the heart of 7085 aluminum is its unique chemistry and treatment process. It’s an aluminum-zinc alloy that’s been enhanced through specialized tempering so that it boasts tensile strengths typically exceeding 540 MPa, rivaling even 7075. But strength isn't its only virtue. 7085 often offers improved fracture toughness and better stress corrosion resistance — two qualities highly coveted in aerospace and defense applications.
Chemical Composition
To understand 7085’s characteristics, l
| Element | Content (wt%) |
|---|---|
| Zinc (Zn) | 7.8 – 8.5 |
| Magnesium (Mg) | 1.2 – 1.8 |
| Copper (Cu) | 1.8 – 2.4 |
| Chromium (Cr) | 0.04 – 0.20 |
| Iron (Fe) | ≤ 0.15 |
| Silicon (Si) | ≤ 0.12 |
| Manganese (Mn) | ≤ 0.10 |
| Titanium (Ti) | ≤ 0.15 |
| Others | Balance (Aluminum) |
Each alloying element has a deliberate role — zinc and magnesium form strengthening precipitates, copper refines grain structure, while chromium and titanium contribute to corrosion resistance and grain stability.
Temper Designations and Their Impact
- T6 temper: This means the alloy is solution heat-treated and then artificially aged. T6 temper balances strength and machinability and is the most common for 7085 plates.
- T651 temper: After T6, the material undergoes stress-relieving by stretching, which reduces residual stresses induced during rolling.
Users aiming for the highest mechanical strength often prefer T651 because it offers better dimensional stability, critical for aerospace structural parts.
Standard Implementation and Industrial Usage
7085 aluminum plate production abides by international standards such as:
- ASTM B209: Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate.
- GB/T 3190—2015: The Chinese standard covering chemical compositions.
- Industry-specific standards where 7085 is recognized, especially in aerospace and military manufacturing.
Industries increasingly favor 7085 aluminum plates in structural applications because they need high-strength yet lightweight materials. Examples include:
- Hydraulic components
- Aircraft bulkheads and fuselage frames
- High-performance automotive parts
- Defense-grade lightweight armor
Mechanical Properties of 7085 Aluminum Plate (T6 Temper)
| Property | Typical Value | Unit |
|---|---|---|
| Tensile Strength (σb) | 540 – 580 | MPa |
| Yield Strength (σ0.2) | ~475 | MPa |
| Elongation (A5) | 7 – 10 | % |
| Hardness (HB) | 150 – 160 | Brinell |
| Modulus of Elasticity | ~71 | GPa |
| Density | 2.82 | g/cm³ |
It’s notable that 7085's performance is in many ways a step forward compared to 7075, especially with regard to resistance to stress corrosion cracking and tough thermal cycling.
Practical Takeaways for Material Selection
If you are a materials engineer, procurement specialist, or projector manager evaluating options for lightweight yet sturdy aluminum plates, 7085 merits strong consideration:
- Budget & Availability: While 7085 often commands a premium, the cost is justified by its toughness and fatigue performance, reducing life-cycle risks.
- Manufacturability: It responds well to machining and forming, with proper heat treatment processes minimizing work-hardening or cracking.
- Long-Term Durability: Its enhanced stress corrosion resistance makes 7085 well-suited for marine or high-humidity environments where alloys like 7075 might fail more quickly.