Intent: Selection between general-purpose weldable aluminum and ultra-high-strength aerospace zinc-alloyed aluminum.
Engineering Verdict & When to Choose Each
6061 or 7075: choose for the limiting requirement
By Mat Grades Editorial Desk · Updated 2026-11-14
Choose 6061 when the approved design benefits from its general fabrication route and the supplied condition meets the load. Shortlist 7075 when a qualified strength advantage solves a real constraint in a machined or mechanically joined part. Do not expect a strength upgrade to fix a component whose principal problem is elastic deflection.
The strongest row on either page may belong to a different temper, form or direction from the stock being quoted. Make the supplier identify the actual condition before comparing values. For a thin pocketed component, include movement after unclamping and the finishing route in the machining trial.
A useful fixture review asks whether the geometry can change. If added thickness or a rib resolves deflection, an alloy premium may have little value. If geometry is fixed and yielding controls, compare compatible guaranteed properties and the required fatigue evidence. For welded construction, assess the final weld region rather than treating incoming T6 stock values as unchanged assembly properties.
6061 Aluminum: evidence to check
6061 Aluminum has 35 cataloged property rows. Modulus of Elasticity is reported as 69 GPa (typical; further condition not stated). Electrical Conductivity is reported as 47 % IACS (typical; O Temper). The record identifies ASTM B209 for Sheet & Plate; check its scope and ordered edition. These are source-scoped examples rather than unrestricted design allowables. Read the full row context and certificate before using a value for acceptance; an absent value is not zero or a performance failure.
7075 Aluminum: evidence to check
7075 Aluminum has 29 cataloged property rows. Modulus of Elasticity is reported as 72 GPa (typical; further condition not stated). Electrical Conductivity is reported as 45 % IACS (typical; O Temper). The record identifies ASTM B209 for Sheet & Plate; check its scope and ordered edition. These are source-scoped examples rather than unrestricted design allowables. Read the full row context and certificate before using a value for acceptance; an absent value is not zero or a performance failure.
Four questions before approval
- Does the design fail by yielding or deflection?
- Will the part be welded or mechanically joined?
- Which temper and direction describe the supplied stock?
- Does the quote include distortion control and the final finish?
Check the linked material records for the complete source trail. Read the methodology before comparing minimum requirements with typical measurements. No direct substitution or qualified fabrication procedure is implied.
Material Comparison
Compare verified engineering materials side by side with condition-specific mechanical properties.
| Parameter | 6061 Aluminum | 7075 Aluminum |
|---|---|---|
| Material Family | Aluminum & Aluminum Alloys | Aluminum & Aluminum Alloys |
| Subfamily | Wrought Aluminum Alloys | Wrought Aluminum Alloys |
| AA Designation | 6061 | 7075 |
| UNS Designation | A96061 | A97075 |
| ISO Designation | AlMg1SiCu | AlZn5.5MgCu |
| Element | 6061 Aluminum | 7075 Aluminum |
|---|---|---|
| Si (Silicon) | 0.4 – 0.8% | ≤ 0.4% |
| Fe (Iron) | ≤ 0.7% | ≤ 0.5% |
| Cu (Copper) | 0.15 – 0.4% | 1.2 – 2% |
| Mn (Manganese) | ≤ 0.15% | ≤ 0.3% |
| Mg (Magnesium) | 0.8 – 1.2% | 2.1 – 2.9% |
| Cr (Chromium) | 0.04 – 0.35% | 0.18 – 0.28% |
| Zn (Zinc) | ≤ 0.25% | 5.1 – 6.1% |
| Ti (Titanium) | ≤ 0.15% | ≤ 0.2% |
| OE (Other Elements Each) | OE: ≤ 0.05% each | OE: ≤ 0.05% each |
| OT (Other Elements Total) | ≤ 0.15% | ≤ 0.15% |
| Al (Aluminum) | — | — |
| Property | 6061 Aluminum | 7075 Aluminum |
|---|---|---|
| Density · TYPICALUnit: g/cm³ | 2.7 g/cm³ | 2.8 g/cm³ |
| Mechanical Parameter | 6061 AluminumO | 7075 AluminumO |
|---|---|---|
| Modulus of Elasticity · TYPICALUnit: GPa | 69 GPa | 72 GPa |
| Ultimate Tensile Strength · Cold Finished Rod & Bar · O Temper · TYPICALUnit: MPa | 124 MPa | 228 MPa |
| Yield Strength (0.2% Offset) · Cold Finished Rod & Bar · O Temper · TYPICALUnit: MPa | 55 MPa | 103 MPa |
| Elongation (4D) · Cold Finished Rod & Bar · O Temper · TYPICALUnit: % | 25 % | 17 % |
| Shear Strength · Cold Finished Rod & Bar · O Temper · TYPICALUnit: MPa | 83 MPa | 152 MPa |
| Fatigue Endurance Limit (5x10^8 cycles) · Cold Finished Rod & Bar · O Temper · TYPICALUnit: MPa | 62 MPa | 117 MPa |
| Property | 6061 Aluminum | 7075 Aluminum |
|---|---|---|
| Electrical Conductivity · O Temper · TYPICALCategory: ELECTRICAL • Unit: % IACS | 47 % IACS | 45 % IACS |
| Coefficient of Thermal Expansion · TYPICALCategory: THERMAL • Unit: µm/(m·K) | 23.6 µm/(m·K) | 23.4 µm/(m·K) |
| Solidus Temperature · TYPICALCategory: THERMAL • Unit: °C | 582 °C | 532 °C |
| Liquidus Temperature · TYPICALCategory: THERMAL • Unit: °C | 652 °C | 635 °C |
| Thermal Conductivity · O Temper · TYPICALCategory: THERMAL • Unit: W/(m·K) | 180 W/(m·K) | 173 W/(m·K) |
| Hardness Scale | 6061 Aluminum | 7075 Aluminum |
|---|---|---|
| HB Hardness · Cold Finished Rod & Bar · O Temper · TYPICAL | 30 HB | 60 HB |