Aluminum 7075-T6 vs. Copper C12200

Compare Aluminum 7075-T6 vs. Copper C12200 strength, stiffness, weight and thermal properties.

Mechanical	Aluminum 7075-T6	Copper C12200
Yield strength	503MPa17.29x stronger	69MPa2
Ultimate tensile strength	572MPa12.59x stronger	221MPa2
Elongation at break	11%1	45%24.09x more ductile
Young's modulus (stiffness)	71GPa1	117GPa21.65x stiffer
Density	2,800kg/m³33.19x lighter	8,941kg/m³2
Strength to weight	180kN·m/kg23.3x higher	7.72kN·m/kg
Stiffness to weight	25.4MN·m/kg1.93x higher	13.1MN·m/kg
Poisson's ratio	0.334	0.345
Shear modulus	26.7GPa	43.7GPa1.64x stiffer in shear
Bulk modulus	69.6GPa	122GPa1.75x higher
Speed of sound	5,036m/s39% faster	3,621m/s

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	Aluminum 7075-T6	Copper C12200
Thermal conductivity	130W/m·K3	339W/m·K22.61x more heat through a fin
Thermal expansion	23.4µm/m·K3	16.9µm/m·K238% less
100 mm part over a 50 °C swing	117µm growth	84.5µm growth38% less
Specific heat	960J/kg·K32.49x higher	385J/kg·K2
Heats up and cools (diffusivity)	48.4mm²/s	98.5mm²/s2.04x faster
Thermal shock resistance	26,370W/m3.38x more resistant	7,799W/m
Melting point	melting range532–635°C3	liquidus1,083°C2

Thermal conductivity against densityHigher and further left: spreads more heat for its weight

Thermal expansion against thermal conductivityLower and further right: warps less when heated

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Sources5 documents: Kaiser Aluminum, Copper Development Association, U.S. Department of Defense, Wieland

Aluminum 7075-T6: 7075-T6/T651, Kaiser Aluminum rod & bar (mechanical) and sheet/coil/plate (physical) typical datasheets; Poisson from MIL-HDBK-5J
Copper C12200: C12200 phosphorus-deoxidized copper (DHP, the air-conditioning and refrigeration tube copper), tube annealed to 0.050 mm grain size (OS050), 0.065 in. wall, copper.org typical values

1
Alloy 7075 Rod & Bar Technical DataKaiser Aluminumarchived copyAluminum 7075-T6 · Yield strength: typical, 0.2% offset, .500 in dia specimenAluminum 7075-T6 · Ultimate tensile strength: typicalAluminum 7075-T6 · Elongation at break: typical, in 4DAluminum 7075-T6 · Young's modulus (stiffness): typical
2
C12200 Alloy (copper.org)Copper Development Associationarchived copyCopper C12200 · Yield strength: typical, 0.5% extension under load, 0.065 in. tubeCopper C12200 · Ultimate tensile strength: typical, 0.065 in. tubeCopper C12200 · Elongation at break: typical, 0.065 in. tubeCopper C12200 · Young's modulus (stiffness): typicalCopper C12200 · Density: nominalCopper C12200 · Thermal conductivity: typical, 20 °CCopper C12200 · Thermal expansion: typical, mean 20-100 °CCopper C12200 · Specific heat: typical, 20 °CCopper C12200 · Melting point: liquidus
3
Alloy 7075 Sheet, Coil & Plate Technical DataKaiser Aluminumarchived copyAluminum 7075-T6 · Density: nominalAluminum 7075-T6 · Thermal conductivity: typical, 20 °C, T651Aluminum 7075-T6 · Thermal expansion: typical, mean 20-100 °CAluminum 7075-T6 · Specific heat: typical, at 100 °CAluminum 7075-T6 · Melting point: melting range
4
MIL-HDBK-5J, Metallic Materials and Elements for Aerospace Vehicle Structures (2003)U.S. Department of DefenseAluminum 7075-T6 · Poisson's ratio: typical (handbook physical constant)
5
Wieland-K19 (Cu-DHP, C12200) Data SheetWielandarchived copyCopper C12200 · Poisson's ratio: reference value at room temperature (Wieland-K19 = Cu-DHP = C12200, rolled products)

Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Mechanical

Is Aluminum 7075-T6 stronger than Copper C12200?

Aluminum 7075-T6 is stronger: its yield strength is 503 MPa against 69 MPa for Copper C12200 (7.29x).

Which is lighter, Aluminum 7075-T6 or Copper C12200?

Aluminum 7075-T6 is lighter: 2,800 kg/m³ against 8,941 kg/m³ for Copper C12200.

Which is stiffer, Aluminum 7075-T6 or Copper C12200?

Copper C12200 is stiffer: Young's modulus 117 GPa against 71 GPa for Aluminum 7075-T6, so the same part in Copper C12200 deflects less under the same load.

Which is lighter for the same job, Aluminum 7075-T6 or Copper C12200?

For the same stiffness or strength: Aluminum 7075-T6 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.

Part that must be	Aluminum 7075-T6	Copper C12200
Stiff rod or tie (tension)	lighter	1.93x heavier
Stiff beam (bending)	lighter	2.49x heavier
Stiff panel or plate	lighter	2.7x heavier
Strong rod or tie	lighter	23.3x heavier
Strong beam	lighter	12x heavier
Strong panel or plate	lighter	8.62x heavier

For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).

Which is more ductile, Aluminum 7075-T6 or Copper C12200?

Copper C12200 stretches further before it breaks: 45% elongation at break against 11% for Aluminum 7075-T6.

Thermal

Which conducts heat better, Aluminum 7075-T6 or Copper C12200?

Copper C12200 conducts heat better: 339 W/m·K against 130 W/m·K for Aluminum 7075-T6.

Which expands less with temperature?

Copper C12200 expands less: 16.9 µm/m·K against 23.4 µm/m·K for Aluminum 7075-T6.