Thermal conductivity against densityHigher and further left: spreads more heat for its weightThermal expansion against thermal conductivityLower and further right: warps less when heated
Try it on a partA bracket to run stress or thermal on, free in your browser
Alloy 6061 Sheet, Coil & Plate Technical DataKaiser Aluminumarchived copyAluminum · Yield strength: typical, 0.2% offset, .500 in dia specimenAluminum · Ultimate tensile strength: typicalAluminum · Elongation at break: typical, in 4D, 0.500 in dia specimenAluminum · Young's modulus (stiffness): typicalAluminum · Density: nominalAluminum · Thermal conductivity: typical, 20 °CAluminum · Thermal expansion: typical, mean 20-100 °CAluminum · Specific heat: typical, at 100 °CAluminum · Melting point: solidus-liquidus
2
Elektron AZ31B Sheet, Plate & Coil (Datasheet 482)Magnesium Elektronarchived copyMagnesium AZ31B-H24 · Yield strength: typical, H24, 0.5-6 mm, 0.2 % proof stressMagnesium AZ31B-H24 · Ultimate tensile strength: typical, H24, 0.5-6 mmMagnesium AZ31B-H24 · Elongation at break: typical, H24, 0.5-6 mm, gauge 5.65√AMagnesium AZ31B-H24 · Thermal conductivity: typical (temper/temperature not stated)Magnesium AZ31B-H24 · Thermal expansion: typical (temperature range not stated)Magnesium AZ31B-H24 · Specific heat: typical
3
MIL-HDBK-5J, Metallic Materials and Elements for Aerospace Vehicle Structures (2003)U.S. Department of DefenseMagnesium AZ31B-H24 · Young's modulus (stiffness): typical (handbook physical constant)Magnesium AZ31B-H24 · Density: nominalAluminum · Poisson's ratio: typical (handbook physical constant)Magnesium AZ31B-H24 · Poisson's ratio: typical (handbook physical constant)Magnesium AZ31B-H24 · Max service temperature: stated application limit
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 stronger than Magnesium AZ31B-H24?
Aluminum is stronger: its yield strength is 276 MPa against 220 MPa for Magnesium AZ31B-H24 (25%).
Which is lighter, Aluminum or Magnesium AZ31B-H24?
Magnesium AZ31B-H24 is lighter: 1,769 kg/m³ against 2,700 kg/m³ for Aluminum.
Which is stiffer, Aluminum or Magnesium AZ31B-H24?
Aluminum is stiffer: Young's modulus 68.3 GPa against 44.8 GPa for Magnesium AZ31B-H24, so the same part in Aluminum deflects less under the same load.
Which is lighter for the same job, Aluminum or Magnesium AZ31B-H24?
For the same stiffness or strength: Magnesium AZ31B-H24 is lighter for a stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.
Part that must be
Aluminum
Magnesium AZ31B-H24
Stiff rod or tie (tension)
about equal
about equal
Stiff beam (bending)
24% heavier
lighter
Stiff panel or plate
33% heavier
lighter
Strong rod or tie
22% heavier
lighter
Strong beam
31% heavier
lighter
Strong panel or plate
36% 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 or Magnesium AZ31B-H24?
Aluminum stretches further before it breaks: 17% elongation at break against 13% for Magnesium AZ31B-H24.
Thermal
Which conducts heat better, Aluminum or Magnesium AZ31B-H24?
Aluminum conducts heat better: 167 W/m·K against 76.9 W/m·K for Magnesium AZ31B-H24.
Which expands less with temperature?
Aluminum expands less: 23.6 µm/m·K against 26.8 µm/m·K for Magnesium AZ31B-H24.