Introduction to 2A02 Aluminum Alloy
2A02 aluminum alloy (formerly known as LY2) is a commonly used heat-resistant duralumin, belonging to the Al-Cu-Mg series aluminum alloys. It features high strength, excellent heat resistance, and good processability, making it widely applied in industrial fields.
I. Basic Information
Material Name: 2A02 aluminum alloy
Former Designation: LY2 (where “LY” is the pinyin abbreviation for “duralumin,” an early naming convention for duralumin alloys in China)
Standards: Mainly complies with industry standards such as Chemical Composition of Wrought Aluminum and Aluminum Alloys (YS/T 439-2001), and can also refer to general aluminum alloy standards like GB/T 3190.
II. Chemical Composition (mass fraction, %)
Element Content Range Element Content Range
Aluminum (Al) Remainder Magnesium (Mg) 2.0% – 2.4%
Copper (Cu) 2.6% – 3.2% Zinc (Zn) ≤0.10%
Manganese (Mn) 0.45% – 0.7% Titanium (Ti) ≤0.15%
Silicon (Si) ≤0.30% Iron (Fe) ≤0.30%
Other Impurities Single ≤0.05%, total ≤0.10% – –
Note: Strict control of impurity content (e.g., Fe, Si) can reduce adverse effects on the alloy’s plasticity and corrosion resistance.
III. Core Properties
1. Mechanical Properties (after heat treatment, e.g., quenching + artificial aging)
Tensile Strength: ≥430 MPa (capable of withstanding large tensile loads)
Proof Yield Strength: ≥275 MPa (maximum load capacity before plastic deformation)
Elongation (δ5): ≥10% (exhibits certain plasticity, facilitating forming)
Hardness (HB): ≥105 (significantly increased after aging treatment)
2. Key Characteristics
Excellent Heat Resistance: As a heat-resistant duralumin, it retains good mechanical properties in high-temperature environments of 150℃ – 200℃, suitable for long-term load-bearing under elevated temperatures.
Heat-Treatable Strengthening: Its strength and hardness can be significantly improved through “quenching (heating to 495 – 505℃ followed by water quenching) + artificial aging (holding at 170 – 180℃ for 10 – 16 hours).”
Good Processability: It has high plasticity during hot deformation, making it easy to form into plates, bars, and forgings through hot working processes such as forging, extrusion, and rolling. It also has moderate cold working performance, allowing for cutting, drilling, and other machining operations.
Weldability and Corrosion Resistance: Its weldability is better than some heat-resistant duralumins (e.g., 2A70), but attention should be paid to strength loss after welding. It has a certain tendency to stress corrosion cracking; thus, during use, it is necessary to avoid long-term exposure to high-stress and corrosive environments (e.g., humid or salty environments). Surface treatments (such as anodizing and painting) are recommended when necessary.
IV. Processing Technologies
Hot Working:
Forging: Conducted at 400 – 470℃, suitable for producing high-strength, complex-shaped forgings (e.g., aerospace structural components).
Extrusion and Rolling: Can be processed into plates, bars, and pipes for components requiring strength and heat resistance.
Heat Treatment:
Quenching: Rapid cooling to retain a supersaturated solid solution, laying the foundation for age strengthening.
Artificial Aging: Enhances alloy strength by precipitating strengthening phases (e.g., Al₂CuMg).
Surface Treatment:
Anodizing: Forms an oxide film to improve corrosion resistance and surface hardness.
Painting or Electroplating: Further enhances corrosion resistance while improving appearance.
V. Application Fields
Aerospace: Widely used in manufacturing aircraft engine compartment components, wing load-bearing parts, and spacecraft high-temperature-resistant structural parts, leveraging its high strength and heat resistance.
Mechanical Manufacturing: Applied in producing components working under high temperatures, such as compressor pistons, molds, and high-strength bolts.
Other Fields: Used as structural materials in high-end equipment (e.g., precision instruments, military equipment) or for custom parts requiring a balance of strength and heat resistance.
Summary
The core advantages of 2A02 (LY2) aluminum alloy lie in its high strength and heat resistance, making it suitable for medium-to-high temperature, high-load scenarios. However, its tendency to stress corrosion cracking requires careful consideration in design and application. Its reliability can be effectively improved through process optimization (e.g., stress relief treatment) and protective measures.