Aluminum 7178-O

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. %
Al85.3 - 89.5 
Cr0.18 - 0.28 
Cu1.6 - 2.4 
FeMax 0.5 
Component   Wt. %
Mg2.4 - 3.1 
MnMax 0.3 
Other, eachMax 0.05 
Other, totalMax 0.15 
Component   Wt. %
SiMax 0.4 
TiMax 0.2 
Zn6.3 - 7.3 

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

Physical PropertiesMetricEnglishComments
Density2.83 g/cc0.102 lb/in AA; Typical

Mechanical Properties
Hardness, Brinell6060 500 kg load with 10 mm ball
Hardness, Knoop8080 Converted from Brinell Hardness Value
Hardness, Vickers6868 Converted from Brinell Hardness Value
Ultimate Tensile Strength228 MPa33000 psi AA; Typical
Tensile Yield Strength103 MPa15000 psi AA; Typical
Elongation at Break15 %15 % AA; Typical; 1/16 in. (1.6 mm) Thickness
Elongation at Break16 %16 % AA; Typical; 1/2 in. (12.7 mm) Diameter
Modulus of Elasticity71.7 GPa10400 ksi AA; Typical; Average of tension and compression. Compression modulus is about 2% greater than tensile modulus.
Poisson's Ratio0.330.33 Estimated from trends in similar Al alloys.
Shear Modulus27 GPa3920 ksi Estimated from similar Al alloys.
Shear Strength150 MPa21800 psi 

Electrical Properties
Electrical Resistivity4.6e-006 ohm-cm4.6e-006 ohm-cm Estimated from other heat treatments.

Thermal Properties
CTE, linear 68F23.4 m/m-C13 in/in-F AA; Typical; Average over 68-212F range.
CTE, linear 250C25.4 m/m-C14.1 in/in-F Average over the range 20-300C
Specific Heat Capacity0.856 J/g-C0.205 BTU/lb-F 
Thermal Conductivity150 W/m-K1040 BTU-in/hr-ft-F Estimated from other heat treatments.
Melting Point477 - 629 C890 - 1165 F AA; Typical range based on typical composition for wrought products 1/4 inch thickness or greater. Homogenization may raise eutectic melting temperature 20-40F but usually does not eliminate eutectic melting.
Solidus477 C890 F AA; Typical
Liquidus629 C1165 F AA; Typical

Processing Properties
Annealing Temperature413 C775 F 
Solution Temperature468 C875 F 

References for this datasheet.

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