Overview of 7050 and 7075 Aluminum
Both 7050 and 7075 aluminum alloys belong to the 7000 series, known for their high strength, lightweight properties, and aerospace applications, with zinc as the primary alloying element. While similar in many aspects, subtle differences in composition, heat treatment, and performance make one alloy more suitable than the other depending on the application.
GNEE: Aluminum 7050 vs 7075 – Strength and Corrosion Resistance
7075-T6: Offers maximum tensile and yield strength, making it ideal for high-stress structural components. However, its toughness and fatigue resistance are relatively lower.
7050-T74: Optimized for corrosion resistance and toughness, particularly in thick sections or components subjected to cyclic loads. Fatigue resistance and fracture toughness are superior to 7075, although ultimate strength is slightly lower.
Selection Guidelines:
Choose 7075-T6 for applications where strength is the primary concern and loads are mostly static or low-cycle.
Choose 7050-T74/T76 when toughness, fatigue resistance, and stress corrosion cracking (SCC) resistance are priorities, especially for thick or cyclic-load-bearing structures.
GNEE: Aluminum 7050 vs 7075 – Chemical Composition
| Element | 7050 | 7075 |
|---|---|---|
| Si | 0.12 | 0.40 |
| Fe | 0.15 | 0.50 |
| Cu | 2.0–2.6 | 1.2–2.0 |
| Mn | 0.10 | 0.30 |
| Mg | 1.9–2.6 | 2.1–2.9 |
| Cr | 0.04 | 0.18–0.28 |
| Zn | 5.7–6.7 | 5.1–6.1 |
| Ti | 0.06 | 0.20 |
| Zr | 0.08–0.15 | – |
| Other (Each) | 0.05 | 0.05 |
| Other (Total) | 0.15 | 0.15 |
| Al | Remainder | Remainder |
7050 Aluminum: Contains slightly higher aluminum, copper, and magnesium, along with zirconium, enhancing stress corrosion resistance, toughness, and performance in thick sections.
7075 Aluminum: Slightly higher zinc and lower copper content increase tensile and yield strength, making it one of the strongest aluminum alloys available.
GNEE: Aluminum 7050 vs 7075 – Heat Treatment and Tempering
7075-T6: Undergoes solution heat treatment followed by artificial aging, achieving peak strength. T73 temper is used when improved SCC resistance is needed with some reduction in strength.
7050-T74/T76: Overaged tempers optimize SCC and exfoliation corrosion resistance, particularly in thicker sections.
GNEE: Aluminum 7050 vs 7075 – Mechanical Properties
Strength and Fatigue Performance:
7075-T6: Higher tensile and yield strength, ideal for maximum load-bearing applications.
7050-T74/T76: Slightly lower strength but better toughness, fatigue resistance, and performance in thick sections.
Corrosion Resistance:
7075: Moderate corrosion resistance; more sensitive to SCC in harsh environments.
7050: Excellent SCC and exfoliation resistance due to zirconium addition and overaging process.
Machinability and Processing:
7075: Easier to machine with smooth finishes using proper tooling.
7050: More challenging to machine but higher thermal conductivity helps dissipate heat.
Weldability: Neither is suited for conventional welding, requiring specialized methods such as friction stir welding.
GNEE: Aluminum 7050 vs 7075 – Applications
Aerospace and Defense:
7075: Components needing maximum strength-to-weight ratio, including landing gear, wing spars, and structural elements.
7050: Aerospace structures such as wing skins, fuselage sections, and bulkheads, where thick-section SCC resistance and fatigue performance are critical.
Automotive and Sports Equipment:
7075: High-performance automotive parts and sports equipment (e.g., bicycle frames, climbing gear).
7050: Applications where toughness and fatigue resistance are required.
GNEE: Aluminum 7050 vs 7075 – Cost and Availability
7075: More widely available and cost-effective for standard high-strength applications.
7050: Primarily used in critical aerospace and military applications, generally at a higher cost due to enhanced toughness and corrosion resistance.
