MakeItFrom.com
Menu (ESC)

7178 (AlZn7MgCu, A97178) Aluminum

7178 aluminum is a 7000-series aluminum alloy: the main alloying addition is zinc and it is formulated for primary forming into wrought products. 7178 is the Aluminum Association (AA) designation for this material. In European standards, it will be given as EN AW-7178. AlZn7MgCu is the EN chemical designation. And A97178 is the UNS number.

It has been in use since 1951, but has only received its standard designation in 1954.

It can have the highest tensile strength among the 7000-series alloys in the database.

The properties of 7178 aluminum include ten common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare 7178 aluminum to: 7000-series alloys (top), all aluminum alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Elastic (Young's, Tensile) Modulus

71 GPa 10 x 106 psi

Elongation at Break

4.5 to 12 %

Fatigue Strength

120 to 210 MPa 18 to 31 x 103 psi

Poisson's Ratio

0.32

Shear Modulus

27 GPa 3.9 x 106 psi

Shear Strength

140 to 380 MPa 21 to 55 x 103 psi

Tensile Strength: Ultimate (UTS)

240 to 640 MPa 34 to 93 x 103 psi

Tensile Strength: Yield (Proof)

120 to 560 MPa 18 to 81 x 103 psi

Thermal Properties

Latent Heat of Fusion

370 J/g

Maximum Temperature: Mechanical

180 °C 350 °F

Melting Completion (Liquidus)

630 °C 1170 °F

Melting Onset (Solidus)

480 °C 890 °F

Specific Heat Capacity

860 J/kg-K 0.2 BTU/lb-°F

Thermal Conductivity

130 W/m-K 72 BTU/h-ft-°F

Thermal Expansion

23 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

31 % IACS

Electrical Conductivity: Equal Weight (Specific)

91 % IACS

Otherwise Unclassified Properties

Base Metal Price

10 % relative

Density

3.1 g/cm3 190 lb/ft3

Embodied Carbon

8.2 kg CO2/kg material

Embodied Energy

150 MJ/kg 62 x 103 BTU/lb

Embodied Water

1110 L/kg 130 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

24 to 52 MJ/m3

Resilience: Unit (Modulus of Resilience)

110 to 2220 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

45 points

Strength to Weight: Axial

21 to 58 points

Strength to Weight: Bending

28 to 54 points

Thermal Diffusivity

47 m2/s

Thermal Shock Resistance

10 to 28 points

Alloy Composition

Among wrought aluminum alloys, the composition of 7178 aluminum is notable for containing comparatively high amounts of zinc (Zn) and copper (Cu). Zinc is used to achieve significant increases in strength, at the cost of increased susceptibility to stress corrosion cracking. Among other things, this limits weldability. Copper is used to improve strength. This comes at the cost of a decrease in corrosion resistance and weldability.

Aluminum (Al) 85.4 to 89.5
Zinc (Zn) 6.3 to 7.3
Magnesium (Mg) 2.4 to 3.1
Copper (Cu) 1.6 to 2.4
Iron (Fe) 0 to 0.5
Chromium (Cr) 0.18 to 0.28
Silicon (Si) 0 to 0.4
Manganese (Mn) 0 to 0.3
Titanium (Ti) 0 to 0.2
Residuals 0 to 0.15

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

ASTM B221: Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes

Handbook of Aluminum vol. 2: Alloy Production and Materials Manufacturing, George Totten and D. Scott MacKenzie (editors), 2003

ASTM B209: Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate

Aluminum Standards and Data, Aluminum Association Inc., 2013

ASM Specialty Handbook: Aluminum and Aluminum Alloys, J. R. Davis (editor), 1993

ISO 6361-2: Wrought aluminium and aluminium alloys - Sheets, strips and plates - Part 2: Mechanical properties

EN 573-3: Aluminium and aluminium alloys. Chemical composition and form of wrought products. Chemical composition and form of products