1. What Is 7075 Aluminum Alloy and Why Is It Considered a High-Strength Material?
7075 aluminum alloy is a premium Al-Zn-Mg-Cu series aluminum alloy known for its exceptional mechanical strength. It was originally developed for aerospace applications, where materials must meet strict requirements for strength, weight reduction, and reliability.
The primary alloying element in 7075 aluminum is zinc, supported by magnesium and copper. Through controlled heat treatment, these elements form strengthening precipitates within the aluminum matrix, significantly increasing tensile and yield strength.
Compared with conventional aluminum alloys, 7075 aluminum offers:
Extremely high tensile and yield strength
Excellent strength-to-weight ratio
Good fatigue resistance
Because of these advantages, GNEE 7075 aluminum plates, sheets, and bars are widely used in aerospace, transportation, and high-load industrial applications.
2. Why Can the Strength of 7075 Aluminum Be Comparable to Steel?
The reason 7075 aluminum can achieve strength levels close to some steels lies in its alloy design and precipitation-hardening mechanism.
Zinc plays a key role by combining with magnesium and copper during heat treatment to form fine intermetallic compounds such as MgZn₂. These precipitates effectively block dislocation movement, which is the main source of plastic deformation in metals.
After solution heat treatment, quenching, and artificial aging:
Tensile strength can reach 540–570 MPa
Yield strength can exceed 480–500 MPa
Although steel may still have higher absolute strength, aluminum weighs only about one-third of steel. This gives 7075 aluminum an outstanding specific strength, making it ideal for lightweight structural design.
3. What Is the Difference Between 7075-T6 and 7075-T651 Aluminum?
The difference between 7075-T6 and 7075-T651 aluminum lies not in chemical composition, but in stress control during heat treatment.
T6 temper: Solution heat-treated, quenched, and artificially aged
T651 temper: T6 process + controlled stretching (1–3%) for stress relief
The additional stretching step in T651 significantly reduces internal residual stress, resulting in:
Better dimensional stability
Less deformation during machining
Improved fatigue and stress corrosion resistance
For high-precision machining and thick plate applications, GNEE recommends 7075-T651 aluminum, while T6 remains suitable for applications where cost and maximum strength are the primary concerns.
