7075 Aluminium Alloy

7075 Aluminium Alloy

7075 aluminium is an alloy of aluminium and zinc, which offers the highest strength of the commercially available alloys, comparable to many steels. 7075 aluminium alloy's composition roughly includes 5.6–6.1% zinc, 2.1–2.5% magnesium, 1.2–1.6% copper, and less than a half percent of silicon, iron, manganese, titanium, chromium, and other metals. High fatigue resistance and fair machinability are also some of 7075 aluminum’s favorable qualities; however it is less resistant to corrosion than many other aluminium alloys. Due to their high strength-to-density ratio, 7075 is used in the commercial aircraft, aerospace, defense equipment and sports equipment industries.

Aluminium 7075 is available in several types of tempers such as T6, T651, T73, T7351 and T76. The superior stress corrosion resistance of the T173 and T7351 tempers makes alloy 7075 a logical replacement for 2024, 2014 and 2017 in many of the most critical applications. The T6 and T651 tempers have fair machinability.

T6 temper has the highest strength but lowest toughness and resistance to stress-corrosion cracking. Since toughness decreases with a decrease in temperature, the T6 temper is not generally recommended for cryogenic applications. The T73 temper provides much improved stress-corrosion resistance over T6 temper with a decrease in strength. The T76 temper provides improved exfoliation resistance and limited stress corrosion resistance over T6 temper with some decrease in strength.

All 7075 aluminium is produced by a heat treating process called forging, which takes place at or around 700°F. It is machined in the annealed condition at 900°F for two hours using oil lubricants and then quenched in cold water. Finally, an aging process called precipitation strengthening is done for 24 hours, where it is heated to 250°F and then cooled. Depending on the temper grade, different amounts of heat and processing times are applied during the 7075-forging process.

7075 aluminium is available in rods, bars, sheets and structural plates up to four inches thick.

Physical Properties

Density: 2.8 g/cm3

Melting Point: Approx 483°C

Thermal Properties

Co-Efficient of Thermal Expansion (20-100°C): 23.2 (10-6/ºC)

Thermal Conductivity: 130 W/mK

Mechanical Properties 

Tensile Strength:         83,000 PSI
Yield Strength:            73,000 PSI
Elongation:                 11%

Alloy Designation US US Federal European UK Other
7075 AMS 4038 7075-T651 Superseded by AMS 4045 QQ-A-250/13 7075-0 Alclad sheet and plate EN 2127 BS 2 L95 Alloy 7075-T651 Plate AIR 9048.690 7075-T7351 Plate
7075 AMS 4039 7075-T651 Superseded by AMS 4049 QQ-A-250/13 7075-T6 Alclad sheet and plate BS 2 L88 Alloy 7075-T6 Clad Sheet and Strip AIR 9048.700 7075-T7351 Plate
7075 AMS 4044 7075 -0 Sheet and Plate QQ-A-250/18 7075-0 Clad one side, sheet and plate BS L160 Alloy 7075-T73511 Bars and Sections AIR 9048.710 7075-T7351 Plate
7075 AMS 4045 7075-T6 Sheet and T651 Plate QQ-A-250/18 7075-T6 Clad one side, sheet and plate BS L161 Alloy 7075 Forging Stock and Forgings� AIR 9049
7075 AMS 4046 7075-T6 Alclad one side Sheet, T651 Plate QQ-A-250/24 7075-T7651 Plate BS L162 Alloy 7075 Forging Stock and Forgings�
7075 AMS 4048 7075-T0 Alclad Sheet and Plate QQ-A-250/25 7075 Sheet, clad with7072-T76 BS L170 Alloy 7075-T6511 Bars and Sections
7075 AMS 4049 7075 -T6 Alclad Sheet and T651 Plate QQ-A-250/26 7075 Sheet, clad with7011-T76 DTD 5110 7075 Clad Plate
7075 AMS 4078 7075-T351 Plate� QQ-A-367 Alloy 7075-T6 Forgings DTD 5124 7075 Bars and Sections
7075 AMS 4122 7075-T6 Cold finished rod, bar, wire MIL-A-22771
7075 AMS 4123 7075-T651 Cold finished bar, rod�
7075 AMS 4124 7075-T7351 Cold finished bar, rod, wire
7075 AMS 4126 7075-T6 Forgings�
7075 AMS 4131 7075-T74 Forgings
7075 AMS 4139 7075 Forgings (Non-Current)
7075 AMS 4141 7075-T73 Die Forgings�
7075 AMS 4147 7075-T7352 Forgings
7075 AMS 4154 7075-T6 Extrusions�
7075 AMS 4166 7075-T73 Extrusion
7075 AMS 4167 7075-T73511 Extrusions�
7075 AMS 4168 7075-T6511 Extrusions Unstraightened
7075 AMS 4169 7075-T6511 Extrusions Straightened�
7075 AMS 4174 7075-T73 Flash Welded Rings
7075 AMS 4186 7075-TF Cold finished bar, rod, wire
7075 AMS 4187 7075-0 Cold finished bar, rod, wire
Characteristics Al 7075-T6, T651 Al 7075-T73, T7351
General resistance to corrosion Rated C (Should be protected against corrosion at least on laying surfaces) Rated C (Should be protected against corrosion at least on laying surfaces)
Stress-corrosion cracking Rated C (Service failures with sustained tension stress acting in short transverse direction relative to grain structure; limited failures in laboratory tests of short transverse specimens) Rated B (No known instance of failure in service; limited failures in laboratory tests for short transverse specimens)
Workability (Cold) Rated D (Ratings are A through D) Rated D (Ratings are A through D)
Machineability Rated B (Ratings are A through E) Rated B (Ratings are A through E)
Brazeability, Gas and Arc Welding Rated D (No commonly used welding methods have been developed) Rated D (No commonly used welding methods have been developed)
Resistance Spot and Seem Welding Rated B (Weldable with special techniques) Rated B (Weldable with special techniques)