Yield Strength of Aluminum Alloys: Chart, Applications & Comparison

Aluminum alloys are widely used in engineering because of their lightweight nature, corrosion resistance, and excellent strength-to-weight ratio. One of the most important mechanical properties that determines whether an alloy is suitable for load-bearing applications is its yield strength.

This article explains what yield strength is, why it matters for aluminum alloys, how it compares with other metals like steel, and provides a comprehensive chart of yield strength values for common aluminum alloys used in die casting and other manufacturing processes.

What is Yield Strength?

From an engineering perspective, yield strength is the maximum stress a material can withstand before it undergoes permanent deformation. In simple terms, it’s the point at which aluminum will no longer return to its original shape once the load is removed.

• Stress = Load applied per unit area (N/m², MPa, or ksi).
• If the applied stress stays below yield strength, the material behaves elastically and springs back.
• If the applied stress exceeds yield strength, the material deforms permanently.

⚖️ Tensile strength vs. yield strength:

• Tensile strength = maximum load a material can handle before fracture.
• Yield strength = load at which permanent deformation begins.
  Both are important, but yield strength is critical for designing safe, long-lasting components.

Why Yield Strength Matters in Aluminum Alloys

Pure aluminum (99%+) has a relatively low yield strength of ~30 MPa (4 ksi). However, by adding alloying elements (copper, magnesium, silicon, zinc) and applying heat treatments (e.g., T4, T6), yield strength can reach 425+ MPa.

Yield strength directly affects:

• Load-bearing capacity – Can the component withstand forces without deformation?
• Structural reliability – Ensures dimensional accuracy over time.
• Material selection – Choosing the right alloy saves costs and avoids over-engineering.

Factors That Influence Aluminum Yield Strength

1. Alloying Elements – Different series (2xxx, 5xxx, 6xxx, 7xxx) deliver different strength levels.
2. Heat Treatment (T-designations) – Solution treatment, aging, and over-aging significantly change strength.
3. Work Hardening (H-designations) – Cold working increases strength in non-heat-treatable alloys.
4. Temperature – Yield strength decreases at elevated temperatures.
5. Manufacturing Process – Die casting, forging, extrusion, or rolling can all affect strength.

Yield Strength of Common Aluminum Alloys

Below is a reference chart of popular aluminum alloys with their temper designations and yield strength values.

Aluminum vs Steel Yield Strength

• Steel typically offers higher yield strength than aluminum.
• However, aluminum provides a superior strength-to-weight ratio, making it ideal for aerospace, automotive, and lightweight structures.

Applications of Aluminum Alloys by Yield Strength

• Lower yield strength alloys (100–200 MPa):
  • Architectural elements, consumer goods, packaging, roofing sheets.
• Medium yield strength alloys (200–350 MPa):
  • Automotive panels, pipelines, marine applications, industrial components.
• High yield strength alloys (350–480+ MPa):
  • Aerospace frames, defence equipment, motorsport, precision engineering.