Aluminum 7178-O

Aluminum 7075-T73; 7075-T735x

Subcategory: 7000 Series Aluminum Alloy; Aluminum Alloy; Metal; Nonferrous Metal

Close Analogs:

Composition Notes:
This designation is considered the sole original alloy for this alloy family.
Aluminum content reported is calculated as remainder.
Composition information provided by the Aluminum Association and is not for design.

Key Words: UNS A97178; Aluminium 7178-O; AA7178-O

Component    Wt. %
Al 85.3 – 89.5
Cr 0.18 – 0.28
Cu 1.6 – 2.4
Fe Max 0.5
Component    Wt. %
Mg 2.4 – 3.1
Mn Max 0.3
Other, each Max 0.05
Other, total Max 0.15
Component    Wt. %
Si Max 0.4
Ti Max 0.2
Zn 6.3 – 7.3

Material Notes: 
Data points with the AA note have been provided by the Aluminum Association, Inc. and are NOT FOR DESIGN.

Physical Properties

Physical Properties Metric English Comments
Density 2.81 g/cc 0.102 lb/in³  AA; Typical

Mechanical Properties

Hardness, Brinell 60 60  500 kg load with 10 mm ball
Hardness, Knoop 80 80  Converted from Brinell Hardness Value
Hardness, Vickers 68 68  Converted from Brinell Hardness Value
Ultimate Tensile Strength 228 MPa 33000 psi  AA; Typical
Tensile Yield Strength 103 MPa 15000 psi  AA; Typical
Elongation at Break 15 % 15 %  AA; Typical; 1/16 in. (1.6 mm) Thickness
Elongation at Break 16 % 16 %  AA; Typical; 1/2 in. (12.7 mm) Diameter
Modulus of Elasticity 71.7 GPa 10400 ksi  AA; Typical; Average of tension and compression. Compression modulus is about 2% greater than tensile modulus.
Poisson’s Ratio 0.33 0.33  Estimated from trends in similar Al alloys.
Shear Modulus 27 GPa 3920 ksi  Estimated from similar Al alloys.
Shear Strength 150 MPa 21800 psi

Electrical Properties

Electrical Resistivity 4.6e-006 ohm-cm 4.6e-006 ohm-cm Estimated from other heat treatments.

Thermal Properties

CTE, linear 68°F 23.4 µm/m-°C 13 µin/in-°F  AA; Typical; Average over 68-212°F range.
CTE, linear 250°C 25.4 µm/m-°C 14.1 µin/in-°F  Average over the range 20-300ºC
Specific Heat Capacity 0.856 J/g-°C 0.205 BTU/lb-°F
Thermal Conductivity 150 W/m-K 1040 BTU-in/hr-ft²-°F  Estimated from other heat treatments.
Melting Point 477 – 629 °C 890 – 1165 °F  AA; Typical range based on typical composition for wrought products 1/4 inch thickness or greater. Homogenization may raise eutectic melting temperature 20-40°F but usually does not eliminate eutectic melting.
Solidus 477 °C 890 °F  AA; Typical
Liquidus 629 °C 1165 °F  AA; Typical

Processing Properties

Annealing Temperature 413 °C 775 °F
Solution Temperature 468 °C 875 °F