When engineers and manufacturers choose aluminum, one property often makes or breaks performance: yield strength. This value defines the exact stress point at which aluminum stops being elastic and begins to deform permanently.

To illustrate why it matters, we’ll examine alloy-specific yield strengths—from the versatile 6061-T6 to the aerospace-grade 7075-T6. With data-backed comparisons, you’ll see how different alloys perform under stress, and why selecting the right one is essential for safety, efficiency, and cost-effectiveness.

By the end of this article, you’ll not only understand what yield strength of aluminum means but also know which alloys fit best for your specific applications—whether in aerospace, automotive, construction, or general manufacturing.

What Is the Yield Strength of Aluminum?

The yield strength of aluminum is the point at which the metal stops deforming elastically and begins to deform permanently. In engineering terms, it is the stress value that separates safe working loads from irreversible structural damage. Every designer, manufacturer, and buyer working with aluminum must understand this property, because it sets the practical limits of performance.

Definition: 0.2% Offset Yield Strength

Unlike mild steel, which shows a sharp yield point, aluminum requires a standardized method to define yield. The 0.2% offset yield strength is used worldwide. It represents the stress needed to create a permanent strain of 0.2% in the material. This method ensures consistency when comparing different alloys and tempers.

Elastic vs. Plastic Deformation

When aluminum is loaded below its yield strength, it deforms elastically—it will return to its original shape once the stress is removed. When the stress exceeds the yield strength, the deformation becomes plastic—permanent bending or distortion occurs. In practical terms, staying within the elastic range ensures durability and safety, while crossing into plastic deformation risks failure.

PSI vs. MPa: Unit Conversions

Yield strength is expressed in either megapascals (MPa) or pounds per square inch (psi), depending on the region. Quick conversion is essential in international supply chains:

• 1 MPa ≈ 145 psi
• Example: An aluminum alloy with yield strength of 275 MPa equals about 40,000 psi

Getting the units right prevents costly specification errors when reviewing test certificates or placing purchase orders.

Why Yield Strength Matters in Aluminum Manufacturing

The yield strength of aluminum is more than just a number on a datasheet. In manufacturing, it guides material selection, production decisions, and long-term product performance. If misunderstood, it can lead to failures that cost time, money, and safety.

Role in Design Safety and Durability

Engineers rely on yield strength to design structures that resist bending, distortion, and collapse. For example, in aerospace and automotive industries, choosing an alloy with the right yield strength ensures lightweight parts can still handle heavy loads. In construction, it guarantees beams, panels, and supports maintain shape under stress. Without clear yield strength requirements, products risk becoming unsafe or unreliable.

Preventing Material Failure in Harsh Conditions

Many aluminum parts are used in demanding environments—from marine settings to high-temperature industrial systems. If the chosen alloy’s yield strength is too low, the material may deform under normal service conditions. In harsh climates, such as offshore rigs or aerospace applications, exceeding yield limits can result in catastrophic failures. Specifying alloys with proven yield strength values is a safeguard against these risks.

How Yield Strength Affects Part Function

Yield strength directly influences how a component performs in service:

• Thin-walled extrusions: Must resist bending during transport and assembly.
• Machined parts: Require enough yield strength to maintain tolerances during operation.
• Welded structures: Need allowances for reduced yield strength in heat-affected zones.

In all cases, yield strength dictates whether a product will function as intended throughout its lifespan. It defines not only strength but also serviceability and trust in the finished part.

Key Factors That Affect Yield Strength of Aluminum

The yield strength of aluminum is not a fixed value. Instead, it depends on a combination of internal and external factors that shape the way the material performs in real applications. Understanding these variables allows engineers, designers, and manufacturers to predict performance and choose the right alloy and temper.

Alloy Composition

The most important factor is alloy chemistry. Pure aluminum (1000 series) has very low yield strength, often below 40 MPa (5,800 psi). When alloying elements such as copper, magnesium, zinc, manganese, and silicon are added, the yield strength increases dramatically. For example, copper additions in 2024 aluminum improve strength, while zinc and magnesium in 7075 aluminum push yield strength above 500 MPa (73,000 psi).

Heat Treatment and Temper

The same alloy can exhibit vastly different yield strengths depending on temper:

• Annealed (O condition): Soft, low strength, maximum ductility.
• T4 temper: Solution heat-treated and naturally aged, medium strength.
• T6 temper: Solution heat-treated and artificially aged, maximum strength.
  For instance, 6061-O has a yield strength around 55 MPa (8,000 psi), while 6061-T6 reaches 275 MPa (40,000 psi).

Work Hardening and Processing

Mechanical processing such as rolling, forging, or extrusion can increase yield strength through strain hardening. Alloys in the 5000 and 3000 series often rely on work hardening (H-tempers) rather than heat treatment. For example, 5052-H32 gains much higher yield strength than 5052-O simply due to cold working.

Grain Structure and Microstructure

The size and arrangement of grains in aluminum affect how dislocations move under stress. Finer grains generally mean higher yield strength. Manufacturing methods such as casting, extrusion, or additive manufacturing each influence grain structure differently, which impacts performance.

Temperature Effects

Yield strength decreases as service temperature increases. At elevated temperatures, aluminum softens, reducing its ability to carry loads. For example, the yield strength of 6061-T6 drops significantly above 150 °C (300 °F). Conversely, at very low temperatures, yield strength can increase, which is useful in cryogenic applications.

Welding and Joint Efficiency

Welding aluminum often reduces yield strength in the heat-affected zone (HAZ). Alloys such as 6061-T6 may lose up to 40% of their yield strength near welds unless re-heat-treated. That’s why weld design and post-weld heat treatment are critical for maintaining mechanical integrity.

Yield Strength of Common Aluminum Alloys (With Table & Chart)

The yield strength of aluminum depends on both alloy composition and temper designation. Across the aluminum series, yield strength values range from as low as 30 MPa (4,000 psi) in pure aluminum to over 500 MPa (70,000 psi) in aerospace-grade alloys.

Yield Strength by Alloy Series

1000 Series (Essentially Pure Aluminum)

• Very soft, excellent corrosion resistance, low strength.
• 1100-O: ~35 MPa (5,000 psi)
• 1350-O: ~34 MPa (4,900 psi)

2000 Series (Aluminum–Copper Alloys)

• High strength, lower corrosion resistance, common in aerospace.
• 2024-T3: ~325 MPa (47,000 psi)
• 2219-T87: ~370 MPa (54,000 psi)
• 2618-T61: ~310 MPa (45,000 psi)

3000 Series (Aluminum–Manganese Alloys)

• Moderate strength, excellent corrosion resistance.
• 3003-H14: ~95 MPa (14,000 psi)
• 3105-H16: ~110 MPa (16,000 psi)

4000 Series (Aluminum–Silicon Alloys)

• Used mainly for automotive and engine components, moderate strength.
• 4032-T6: ~280 MPa (41,000 psi)

5000 Series (Aluminum–Magnesium Alloys)

• Excellent corrosion resistance, used in marine and transport.
• 5052-H32: ~193 MPa (28,000 psi)
• 5083-H116: ~228 MPa (33,000 psi)
• 5754-H22: ~150 MPa (22,000 psi)

6000 Series (Aluminum–Magnesium–Silicon Alloys)

• Good strength, weldability, and corrosion resistance.
• 6061-T6: ~275 MPa (40,000 psi)
• 6063-T6: ~214 MPa (31,000 psi)
• 6082-T6: ~260 MPa (38,000 psi)

7000 Series (Aluminum–Zinc Alloys)

• Very high strength, used in aerospace and defense.
• 7075-T6: ~503 MPa (73,000 psi)
• 7475-T761: ~465 MPa (67,500 psi)
• 7050-T7451: ~455 MPa (66,000 psi)

Casting Alloys

• Yield strength varies widely depending on silicon content and heat treatment.
• A356-T6: ~230 MPa (33,000 psi)
• A380 (as-cast): ~170 MPa (25,000 psi)
• ADC12 (as-cast): ~160 MPa (23,000 psi)

Quick-Reference Yield Strength Table

Alloy & Temper	Yield Strength (MPa)	Yield Strength (psi)
1100-O	35	5,000
1350-O	34	4,900
3003-H14	95	14,000
3105-H16	110	16,000
5052-H32	193	28,000
5083-H116	228	33,000
5754-H22	150	22,000
6061-T6	275	40,000
6063-T6	214	31,000
6082-T6	260	38,000
2024-T3	325	47,000
2219-T87	370	54,000
2618-T61	310	45,000
4032-T6	280	41,000
7075-T6	503	73,000
7475-T761	465	67,500
7050-T7451	455	66,000
A356-T6 (cast)	230	33,000
A380 (cast)	170	25,000
ADC12 (cast)	160	23,000

Conclusion

The yield strength of aluminum is the foundation for understanding how this versatile metal performs in real-world applications. From the definition of the 0.2% offset yield strength, to the key factors that influence it—such as alloy composition, heat treatment, and temperature—it’s clear that yield strength is not a single number but a property shaped by many variables.

Alloy comparisons, from 1100 and 3003 on the softer end to 6061 and 7075 at high strength, show how wide the range can be. For engineers, designers, and manufacturers, knowing these differences ensures the right balance of safety, performance, and cost.

Whether you are choosing aluminum for aerospace, automotive, marine, or construction, yield strength remains the critical property that defines reliability. By matching the correct alloy and temper to your application, you unlock the full potential of aluminum—lightweight, strong, and built for performance.