Aluminum 1100-O vs. Aluminum 7075-T6

Compare Aluminum 1100-O vs. Aluminum 7075-T6 strength, stiffness, weight and thermal properties.

Mechanical	Aluminum 1100-O	Aluminum 7075-T6
Yield strength	35MPa1	503MPa214.4x stronger
Ultimate tensile strength	90MPa1	572MPa26.36x stronger
Elongation at break	35%13.18x more ductile	11%2
Young's modulus (stiffness)	69GPa1	71GPa2
Density	2,710kg/m³1	2,800kg/m³3
Strength to weight	12.9kN·m/kg	180kN·m/kg13.9x higher
Stiffness to weight	25.5MN·m/kg	25.4MN·m/kg
Poisson's ratio	not sourced	0.334
Shear modulus	not sourced	26.7GPa
Bulk modulus	not sourced	69.6GPa
Speed of sound	5,046m/s	5,036m/s

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	Aluminum 1100-O	Aluminum 7075-T6
Thermal conductivity	222W/m·K11.71x more heat through a fin	130W/m·K3
Thermal expansion	23.6µm/m·K1	23.4µm/m·K3
100 mm part over a 50 °C swing	118µm growth	117µm growth
Specific heat	base material901J/kg·K5	960J/kg·K3
Heats up and cools (diffusivity)	90.9mm²/s1.88x faster	48.4mm²/s
Thermal shock resistance	not sourced	26,370W/m
Melting point	melting range640–655°C1	melting range532–635°C3

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, U.S. Department of Defense, Hydro

Aluminum 1100-O: 1100-O (annealed) commercially pure aluminium, Kaiser Aluminum Tube & Pipe Alloy 1100 Technical Data (Rev. 05/06), typical properties; specific heat from Hydro EN AW-1050A (99.5% Al) extruded-products datasheet (10/2018).
Aluminum 7075-T6: 7075-T6/T651, Kaiser Aluminum rod & bar (mechanical) and sheet/coil/plate (physical) typical datasheets; Poisson from MIL-HDBK-5J

1
Alloy 1100 Tube & Pipe Technical Data, Rev. 05/06Kaiser Aluminumarchived copyAluminum 1100-O · Yield strength: typical, O, 0.0625 in specimenAluminum 1100-O · Ultimate tensile strength: typical, OAluminum 1100-O · Elongation at break: typical, O, in 4DAluminum 1100-O · Young's modulus (stiffness): typicalAluminum 1100-O · Density: nominal, 20 °CAluminum 1100-O · Thermal conductivity: typical, O, 20 °CAluminum 1100-O · Thermal expansion: typical, mean 20-100 °CAluminum 1100-O · Melting point: melting range
2
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
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
Technical Datasheet, Extruded Products: Alloy EN AW-1050AHydroAluminum 1100-O · Specific heat: base material: commercially pure aluminium EN AW-1050A (Hydro), 20 °C

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 1100-O stronger than Aluminum 7075-T6?

Aluminum 7075-T6 is stronger: its yield strength is 503 MPa against 35 MPa for Aluminum 1100-O (14.4x).

Which is lighter, Aluminum 1100-O or Aluminum 7075-T6?

Aluminum 1100-O is lighter: 2,710 kg/m³ against 2,800 kg/m³ for Aluminum 7075-T6.

Which is stiffer, Aluminum 1100-O or Aluminum 7075-T6?

Aluminum 7075-T6 is stiffer: Young's modulus 71 GPa against 69 GPa for Aluminum 1100-O, so the same part in Aluminum 7075-T6 deflects less under the same load.

Which is lighter for the same job, Aluminum 1100-O or Aluminum 7075-T6?

For the same stiffness or strength: Aluminum 1100-O is lighter for a stiff beam (bending), stiff panel or plate; Aluminum 7075-T6 is lighter for a strong rod or tie, strong beam, strong panel or plate.

Part that must be	Aluminum 1100-O	Aluminum 7075-T6
Stiff rod or tie (tension)	about equal	about equal
Stiff beam (bending)	lighter	2% heavier
Stiff panel or plate	lighter	2% heavier
Strong rod or tie	13.9x heavier	lighter
Strong beam	5.72x heavier	lighter
Strong panel or plate	3.67x heavier	lighter

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 1100-O or Aluminum 7075-T6?

Aluminum 1100-O stretches further before it breaks: 35% elongation at break against 11% for Aluminum 7075-T6.

Thermal

Which conducts heat better, Aluminum 1100-O or Aluminum 7075-T6?

Aluminum 1100-O conducts heat better: 222 W/m·K against 130 W/m·K for Aluminum 7075-T6.

Which expands less with temperature?

Aluminum 7075-T6 expands less: 23.4 µm/m·K against 23.6 µm/m·K for Aluminum 1100-O.