What is the difference between 2024-T351 and 2024 T851?
2024-T351 and 2024-T851 aluminum alloys have the same chemical composition, but due to differences in heat treatment and aging processes, they exhibit significant differences in mechanical properties. T351 focuses more on good ductility and toughness, while T851 provides higher strength, making it suitable for more demanding applications.
Here’s a table summarizing the key differences between 2024-T851 and 2024-T351:
| Property | 2024-T851 | 2024-T351 | Difference |
| Brinell Hardness | Higher | Lower | 2024-T851 is harder, more wear-resistant |
| Elongation at Break | Lower | Higher | 2024-T351 is more ductile |
| Shear Strength | Higher | Lower | 2024-T851 is better for high-stress applications |
| Tensile Strength | Higher | Lower | 2024-T851 is stronger overall |
| Tensile Yield Strength | Higher | Lower | 2024-T851 can withstand more stress before plastic deformation |
Both 2024-T351 and 2024-T851 aluminum alloys are highly suitable for high-strength structural components in aerospace and other industrial fields, but their differences lie in the fact that the T851 material has enhanced stability and corrosion resistance through pre-stretching and a more refined heat treatment process. Therefore, 2024-T851 is usually the more ideal choice for more demanding conditions.
2024-T351 Aluminum
The T351 condition refers to the 2024 aluminum alloy that undergoes stress relief and artificial aging after solution treatment (i.e., T351 processing). This condition offers good overall performance, especially in applications where high strength is required. The main features of the T351 condition are as follows:
Stress Relief: After the aluminum alloy ingot undergoes solution treatment, stress relief is performed. This stress relief process helps to reduce residual stress inside the material, making it more stable.
Artificial Aging: After solution treatment, the aluminum alloy undergoes artificial aging to further improve its strength and hardness.
Strength and Corrosion Resistance: 2024 aluminum alloy in the T351 condition has high strength, making it suitable for aerospace structures, mechanical components, and other applications requiring high load-bearing capacity and strength.
2024-T851 Aluminum
The T851 condition is also an aluminum alloy treated with solution treatment and artificial aging, but the difference from T351 lies in the additional step of pre-stretching after the solution treatment. Specifically, the T851 condition includes a stretching operation after heat treatment, which helps to eliminate higher residual stress, thereby improving the material’s stability and performance. The main features of the T851 condition include:
Pre-Stretching: The pre-stretching process in the T851 condition applies a certain amount of tensile stress to further relieve stress after solution treatment. This process significantly reduces residual stress in the material, decreasing the risk of deformation during use.
Enhanced Stability: Due to the pre-stretching process, 2024 aluminum alloy in the T851 condition exhibits better dimensional stability. This makes it more reliable in applications, especially for high-precision aerospace components.
Higher Corrosion Resistance and Stress Corrosion Cracking Resistance: Compared to T351, materials in the T851 condition generally show stronger resistance to stress corrosion cracking, especially in high-strength environments.
2024-T351 and 2024-T851 Mechanical Properties
2024 aluminum alloy in the T851 condition typically exhibits higher stability and stronger stress corrosion cracking resistance than in the T351 condition. Due to the pre-stretching process, T851 material maintains its mechanical properties better over long-term use.
| Property | 2024-T351 Aluminum | 2024-T851 Aluminum |
| Brinell Hardness | 120 | 140 |
| Elastic Modulus (x 10^6 psi) | 10 | 10 |
| Elongation at Break (%) | 13 | 4.9 |
| Fatigue Strength (x 10^3 psi) | 20 | 20 |
| Poisson's Ratio | 0.33 | 0.33 |
| Shear Modulus (x 10^6 psi) | 3.9 | 3.9 |
| Shear Strength (x 10^3 psi) | 41 | 43 |
| Tensile Strength: Ultimate (UTS) (x 10^3 psi) | 67 | 75 |
| Tensile Strength: Yield (Proof) (x 10^3 psi) | 47 | 66 |
2024-T351 and 2024 T851 Thermal Properties
| Property | 2024-T351 Aluminum | 2024-T851 Aluminum |
| Latent Heat of Fusion (J/g) | 390 | 390 |
| Maximum Temperature (Mechanical, °F) | 390 | 390 |
| Melting Completion (Liquidus, °F) | 1180 | 1180 |
| Melting Onset (Solidus, °F) | 930 | 930 |
| Specific Heat Capacity (BTU/lb-°F) | 0.21 | 0.21 |
| Thermal Conductivity (BTU/h-ft-°F) | 70 | 70 |
| Thermal Expansion (µm/m-K) | 23 | 23 |
2024-T351 and 2024 T851 Electrical Properties
| Property | 2024-T351 Aluminum | 2024-T851 Aluminum |
| Electrical Conductivity: Equal Volume (% IACS) | 30 | 30 |
| Electrical Conductivity: Equal Weight (% IACS) | 90 | 90 |
2024-T351 and 2024-T851 Applications
Due to the higher stability of the T851 condition, it is typically used in applications that require stricter conditions, such as structural components in aerospace that must endure long-term load variations and environmental stresses. In contrast, T351 is more commonly used in applications with high strength requirements but less stringent dimensional stability needs.
- 2024 T351: Due to its excellent strength and toughness, 2024-T351 is commonly used in aircraft structural components, aerospace parts, and other applications that need to withstand high loads.
- 2024 T851: Due to its higher strength, 2024-T851 is often used in structural components that require extremely high strength and rigidity, such as critical components in the aerospace industry.
Otherwise Unclassified Properties
| Property | 2024-T351 Aluminum | 2024-T851 Aluminum |
| Base Metal Price (% relative) | 11 | 11 |
| Calomel Potential (mV) | -600 | -600 |
| Density (lb/ft³) | 190 | 190 |
| Embodied Carbon (kg CO2/kg material) | 8.3 | 8.3 |
| Embodied Energy (x 10^3 BTU/lb) | 65 | 65 |
| Embodied Water (gal/lb) | 140 | 140 |
