Aluminum yield strength is the stress level where an aluminum material starts to deform permanently. Below that point, the part can spring back when the load is removed. Above it, the shape, fit or alignment may not recover.
For common aluminum alloys, yield strength can range from very low values of 7 MPa in pure or annealed aluminum to roughly 500 MPa in high-strength 7xxx tempers. The exact value depends on alloy, temper, product form, heat treatment, cold work, test method and temperature. I never treat “aluminum” as one strength number.
What Aluminum Yield Strength Means
Yield strength marks the boundary between elastic deformation and plastic deformation. Elastic deformation is reversible. Plastic deformation is permanent.
For a bracket, housing, rail, extrusion, panel or machined block, yield strength matters because many parts fail functionally before they break. A part can bend, lose flatness, shift hole alignment or stop sealing long before it reaches ultimate tensile strength.
Most engineering tables report yield strength in MPa or ksi. MPa is common in metric data. Ksi means thousand pounds per square inch. One ksi is about 6.895 MPa.
Aluminum Yield Strength Table: Common Alloys And Tempers
Use the table as a starting point, not as a final design value. Values vary by source, product form and specification. For production parts, confirm the alloy, temper and certificate from the material supplier.
| Aluminum alloy and temper | Yield strength, approximate | Common context | Practical note |
|---|---|---|---|
| Pure aluminum / soft commercial aluminum | about 7 MPa | electrical, decorative, non-load-bearing uses | Excellent ductility, low structural strength |
| 1100-H12 | about 76 MPa / 11 ksi | sheet and formed products | Higher than soft pure aluminum, still not a high-strength structural alloy |
| 3003-H18 | about 172 MPa / 25 ksi | sheet, formed components | Work hardening increases strength |
| 5052-H32 | about 159 MPa / 23 ksi | sheet metal, marine, formed parts | Good corrosion resistance and formability with moderate strength |
| 6061-T4 | about 110 MPa / 16 ksi | extrusions, formed or naturally aged condition | Lower than T6, usually better forming than T6 |
| 6061-T6 | about 241-276 MPa / 35-40 ksi | machined parts, extrusions, structural components | Common balance of strength, machinability, corrosion resistance and availability |
| 6063-T6 | about 172 MPa / 25 ksi | architectural extrusions and profiles | Easier extrusion and finishing, lower strength than 6061-T6 |
| 6082-T6 | about 250 MPa | structural profiles and transport applications | Strong 6xxx option, common in some markets |
| 7075-T6 | about 483-505 MPa / 70+ ksi | high-strength aerospace and performance parts | Very strong, but weldability and corrosion behavior need closer review |
| A356-T6/T61 | about 138-193 MPa / 20-28 ksi | cast aluminum parts | Casting process and heat treatment strongly affect properties |
Why Aluminum Yield Strength Values Differ
Different sources can be correct and still show different values. The most common reason is that they are not describing the same material condition.
Alloy chemistry changes yield strength. Magnesium, silicon, copper and zinc can raise strength in different alloy families. That is why 7075-T6 is much stronger than 6063-T6, even though both are aluminum alloys.
Temper changes yield strength. O temper, H temper, T4 and T6 are not formatting details. They describe the mechanical history of the material. Cold work, solution heat treatment and artificial aging can move yield strength dramatically.
Product form matters
Plate, sheet, extrusion, forging and casting can have different property expectations even when the alloy name looks similar. Directionality, thickness, grain structure and process route can change the usable value.
Testing method matters
Many aluminum alloys do not show a sharp yield plateau. The 0.2% offset method is commonly used to define yield strength from the stress-strain curve. When a source does not state the method or standard, treat its table as a reference, not a design specification.
Temperature matters
Aluminum alloys can lose strength at elevated temperatures. A room-temperature value should not be transferred automatically to hot service.
Yield Strength vs Tensile Strength vs Young’s Modulus
Yield strength answers one question: when does permanent deformation begin?
Tensile strength answers a different question: what stress can the material withstand before fracture?
Young’s modulus answers another question: how stiff is the material while it is still in the elastic region?
These properties should not be swapped. A part can be stiff enough but yield too early. Another part can have adequate yield strength but flex too much because aluminum’s modulus is much lower than steel’s. Aluminum alloys usually sit near 69 GPa for elastic modulus, while steel is near 200 GPa. That difference affects deflection even when strength is acceptable.
For design work, I check all three: yield strength for permanent deformation, tensile strength for fracture margin and modulus for deflection. If stiffness is part of your design question, the related guide on shear modulus of aluminum is a useful next read because it explains another elastic property that affects twisting and rigidity.
How To Use Yield Strength In Aluminum Alloy Selection
Start with the part’s real load case. A decorative cover, a CNC fixture, an extrusion frame, a pressure housing and a bent sheet bracket do not need the same alloy logic.
- For general machined aluminum parts, 6061-T6 is often the practical baseline. It has moderate-to-high yield strength, good machinability, broad availability and reasonable corrosion resistance.
- 5052-H32 is often more useful than chasing a higher-strength alloy for sheet metal parts that need forming and corrosion resistance. A stronger alloy can crack during bending or make forming less predictable.
- For aluminum extrusion or profile work, 6063-T6 may be selected because it extrudes and finishes well. Its yield strength is lower than 6061-T6, but strength is not the only requirement in visible profiles.
- Considering high-load lightweight parts, 7075-T6 can be attractive because its yield strength is much higher. The tradeoff is stricter review of corrosion protection, joining method, cost, availability and process route.
- When using cast aluminum, do not transfer wrought-alloy assumptions directly. Casting alloy, heat treatment, porosity control and inspection method can dominate the final mechanical performance.
Can You Use A Chart Value Directly For Design?
Use chart values to screen materials. Do not use them as the final authority for a critical part.
Before a chart value becomes a design input, confirm:
- alloy and temper;
- product form, thickness and specification;
- material certificate or mill test report;
- test method and room-temperature assumption;
- load direction and safety factor;
- welds, bends, machining removal or heat-affected zones;
- surface treatment or corrosion environment;
- fatigue, impact or vibration requirements.
If the part is structural, safety-critical or expensive to fail, an engineer should set the allowable stress and safety factor. Yield strength is a property, not a complete design rule. Surface requirements also belong in that review because anodizing, powder coating and other aluminum surface treatments may affect finish choice, corrosion strategy and inspection planning even when they do not raise the base metal’s bulk yield strength.
Common Mistakes When Reading Aluminum Yield Strength
- Asking for “the yield strength of aluminum” without naming the alloy and temper. The answer for soft pure aluminum is not close to the answer for 7075-T6.
- Comparing yield strength without density, stiffness and process limits. Aluminum can look weaker than steel by volume, but its strength-to-weight ratio may still make it the better choice.
- Ignoring heat treatment. 6061-T4 and 6061-T6 are not interchangeable when permanent deformation matters.
- Using tensile strength as a yield value. Tensile strength is fracture behavior. Yield strength is permanent deformation behavior.
- Forgetting fabrication. Welding, bending, machining, casting and aging can change the usable property at the part level.
Material Certificate Checklist
When yield strength matters, ask the supplier for evidence, not just a catalog value.
Useful documents include:
- material test report or mill certificate;
- alloy and temper confirmation;
- applicable ASTM, EN, GB or customer specification;
- heat number or lot traceability;
- mechanical property table;
- chemical composition;
- product form and dimensions;
- inspection or testing method when required.
For custom aluminum parts, share the drawing, alloy preference, temper, load direction, operating temperature, tolerance requirements and surface treatment before finalizing material choice. That information changes the practical recommendation.
Custom Aluminum Processing Note
Zheng Ji Aluminum is a fit when a project needs coordinated aluminum processing rather than a single isolated step. Extrusion, CNC machining, surface treatment and related fabrication decisions can affect whether the selected alloy and temper still make sense after the part is made.
For a yield-strength-sensitive part, the useful starting point is not only “Can you quote this?” It is: what alloy, temper, process chain, tolerance, surface finish and inspection evidence does the drawing require? Zheng Ji’s custom aluminum processing services are most relevant when those decisions need one coordinated review from extrusion through CNC machining and finishing.
FAQ
What is the yield strength of 6061-T6 aluminum?
Common references place 6061-T6 around 241-276 MPa, or roughly 35-40 ksi. Use the specific value required by the material specification or certificate for the product form you are buying.
Is aluminum yield strength lower than steel?
For the same cross-section, many steels have higher yield strength than many aluminum alloys. The comparison changes when weight matters because aluminum is much less dense than steel.
Is 7075-T6 stronger than 6061-T6?
Yes. 7075-T6 has much higher yield strength than 6061-T6 in common reference tables. It is not automatically the better choice because corrosion behavior, weldability, cost and availability can matter more than peak strength.
Does anodizing change aluminum yield strength?
Anodizing mainly affects the surface. It should not be treated as a way to raise bulk yield strength. If mechanical properties are critical, focus on alloy, temper, product form and heat treatment.
Does welding affect aluminum yield strength?
It can. Welding can reduce strength in the heat-affected zone, especially for heat-treatable alloys. Do not apply base-metal T6 values blindly to welded assemblies.
Review-Stage Source Notes
- Engineering ToolBox: aluminum mechanical properties table
- Gabrian: How Strong is Aluminum
- Weldo Machining: Aluminum Strength Explained
