Technical guide · 2026-08-03
7xxx Aluminum-Zinc Alloys
7xxx wrought alloys use zinc, often with magnesium and copper, to obtain very high strength through precipitation heat treatment. They serve aerospace, tooling and high-performance structures but require deliberate temper selection for toughness, stress-corrosion resistance, fatigue and thick-section quench response.
01
Definition and boundary
The series is a first filter only; exact alloy, temper, product form and governing standard control acceptance and substitution.
Reference information only: final acceptance is controlled by the ordered product specification, condition, dimensions and certified test results.
02
How the material system works
Principal alloying elements define the series and available strengthening response.
Temper records strain hardening and/or thermal processing history.
Thickness, direction and product route influence guaranteed properties.
03
Representative grades and systems
| Grade or system | Selection focus | Qualification |
|---|---|---|
| 7005 | Weldable structural/extrusion alloy for transport frames. | Verify the ordered product specification, condition and dimensions before substitution. |
| 7050 | Aerospace plate/forging alloy emphasizing thick-section toughness and SCC resistance. | Verify the ordered product specification, condition and dimensions before substitution. |
| 7075 | Widely recognized high-strength aerospace and tooling alloy. | Verify the ordered product specification, condition and dimensions before substitution. |
04
Properties and trade-offs
Density remains low, while strength varies widely by alloy and temper.
Corrosion, conductivity and finish response depend on chemistry and surface condition.
Joining can change local temper and usable design strength.
05
Product forms and supply conditions
06
Applications and selection
Applications and selection
- Aircraft structures and highly loaded fittings
- Tooling, molds and precision equipment
- High-performance sporting and transport parts
Properties and trade-offs
- Define structural, corrosion, thermal, electrical, forming and appearance priorities.
- Choose exact alloy and temper for the required product form and section.
- Verify weld-zone properties, galvanic contact and coating/anodizing route.
07
Fabrication, durability and inspection
Use forming, welding and machining practice for the exact alloy-temper and product thickness.
Control heat input because welding can reduce heat-treated or work-hardened strength near the joint.
Prevent embedded steel contamination and manage oxide, cleaning, anodizing or coating compatibility.
08
Procurement checklist
- Specify alloy, temper, product standard, dimensions, tolerances and surface condition as one identity.
- State direction-dependent properties, flatness, residual stress, conductivity, anodizing or corrosion tests when relevant.
- Define film/interleaf protection, packing, moisture control, traceability and certificate requirements.
09
Standards, sources and review
Standards and designation context
- The Aluminum Association international alloy registration records
- ANSI H35 alloy, temper and tolerance systems
- Product-specific ASTM/EN/ISO/AMS or national specifications
Authoritative research sources
The Aluminum Association · Standards portal, accessed 2026
The Aluminum Association · December 2025 registration record
The Aluminum Association · 2024 edition overview