7178 T6 T651 Aluminum Plate

7178 T6 and T651 aluminum alloys are both suitable for aerospace applications, but T651, which undergoes stress-relief and stabilization treatments, is more suited for applications requiring precise dimensions and long-term stability.

• 7178-T6: After solution heat treatment and aging, it has high strength and relatively high ductility.
• 7178-T651: Adds a stress-relief step on top of the T6 treatment, enhancing dimensional stability and toughness, suitable for high-stress applications.

7178 T6 Aluminum Plate

7178-T6 aluminum is a high-strength aluminum alloy, mainly used in aerospace and military applications. To achieve the T6 state, the metal undergoes the following steps:

• Solution heat treatment: In this process, the aluminum alloy is heated to a high temperature, allowing alloying elements (such as zinc) to dissolve into the aluminum matrix, forming a homogeneous solid solution. The goal of this step is to increase the strength of the alloy.
• Artificial aging: After solution heat treatment, the aluminum alloy is rapidly cooled, typically by water quenching or air cooling. It is then aged at a lower temperature (typically between 150°C and 200°C) to promote the formation of precipitates, further strengthening the alloy’s mechanical properties.

7178-T6 aluminum is characterized by good strength and relatively high ductility, especially compared to other variants of 7178 aluminum, with the second-highest ductility. This makes 7178-T6 aluminum highly popular in applications that require strength and toughness.

7178 T6 Aluminum State Characteristics

Mechanical properties:

High strength, suitable for aerospace applications requiring high strength.

Ductility: Among the 7178 variants, it has a relatively high level, aiding in the processing of complex structural components.

7178 T6 Aluminum Applications

Aerospace structural components:

Main beams, skins, and reinforcement frames of aircraft wings.

High-strength parts:

Aircraft fuselage frames.

Large landing gear struts.

7178 T6 Aluminum Advantages and Limitations

Advantages: High strength and fatigue resistance, especially suitable for high-load applications.

Limitations: Relatively poor corrosion resistance, requires coating or anodizing for protection.

7178 T651 Aluminum Plate

7178-T651 aluminum is also a high-strength alloy, primarily used for manufacturing structural components that bear high stresses. The T651 state is achieved through the following steps:

• Solution heat treatment: Like 7178-T6 aluminum, 7178-T651 aluminum first undergoes solution heat treatment to increase the alloy’s strength.
• Stress relief: After solution heat treatment, 7178-T651 aluminum undergoes stress-relief treatment. This process is achieved by stretching the metal by a certain amount, depending on the type of forged product (such as thin sheets, plates, bars, or forgings). This helps reduce internal stress, thereby minimizing the risk of deformation and cracking during subsequent processing.
• Artificial aging: After stress relief, 7178-T651 aluminum undergoes artificial aging to further improve its mechanical properties.

7178-T651 aluminum is characterized by more stable mechanical properties after the stress-relief treatment, making it suitable for high-stress environments. Due to the stress-relief process, 7178-T651 aluminum typically has better dimensional stability and toughness, making it ideal for complex structural components.

7178 T651 Aluminum State Characteristics

Mechanical properties:

High strength with good processing stability.

Stress corrosion resistance is superior to the T6 state.

Stress-relief stretching amount:

Thin sheets and plates: Typically stretched 0.5%-3%.

Bars and forgings: The stretching amount is adjusted based on the complexity and thickness of the shape, usually between 0.5%-1.5%.

7178 T651 Aluminum Applications

Aircraft skins and frames:

More stable dimensions and shape under compressive and tensile mixed environments.

Key aerospace components:

Includes fuel tanks, junction components, and fasteners.

7178 T651 Aluminum Advantages and Limitations

Advantages:

Lower residual stress, reducing the risk of deformation during processing or use.

Improved machining precision and long-term durability in the aerospace industry.

Limitations:

Similar to T6 state, it requires additional corrosion protection.

7178 T6 T651 Aluminum Material Property Data Sheet

What is the difference between T651 and T6 aluminum?

The key difference between T651 and T6 aluminum lies in the additional stress-relieving process applied to T651, which makes it suitable for machining without significant distortion. Below is a breakdown of their differences:

T651 is essentially a T6 alloy with added stress relief for better machining performance and stability.