Aluminum 7075-T6 vs. Solder SAC305

Compare Aluminum 7075-T6 vs. Solder SAC305 strength, stiffness, weight and thermal properties.

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Mechanical
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Yield strength	503MPasourcetypical, 0.2% offset, .500 in dia specimen	22MPasourcetypical
Ultimate tensile strength	572MPasourcetypical14.5x stronger	39.6MPasourcetypical
Elongation at break	11%sourcetypical, in 4D	49%sourcetypical
Young's modulus (stiffness)	71GPasourcetypical	6.9GPasourcetypical, temperature and strain rate not stated
Density	2,800kg/m³sourcenominal	7,350kg/m³sourcetypical
Strength to weight	180kN·m/kg60x higher	2.99kN·m/kg
Stiffness to weight	25.4MN·m/kg27x higher	0.939MN·m/kg
Poisson's ratio	0.33sourcetypical (handbook physical constant)	0.35sourcetypical
Shear modulus	26.7GPa10.4x stiffer in shear	2.56GPa
Bulk modulus	69.6GPa	7.67GPa
Speed of sound	5,036m/s	969m/s
Thermal
Thermal conductivity	130W/m·Ksourcetypical, 20 °C, T651	61W/m·Ksourcetypical, temperature not stated
Thermal expansion	23.4µm/m·Ksourcetypical, mean 20-100 °C	21.9µm/m·Ksourcemean, 20-100 °C (MacDermid Alpha)
100 mm part over a 50 °C swing	117µm growth	110µm growth7% less
Specific heat	960J/kg·Ksourcetypical, at 100 °C	232J/kg·Ksourcetypical (MacDermid Alpha)
Heats up and cools (diffusivity)	48.4mm²/s35% faster	35.8mm²/s
Thermal shock resistance	26,370W/m4.57x more resistant	5,773W/m
Melting point	532–635°Csourcemelting range	217–220°Csourcesolidus-liquidus
Values for	7075-T6/T651, Kaiser Aluminum rod & bar (mechanical) and sheet/coil/plate (physical) typical datasheets; Poisson from MIL-HDBK-5J	SAC305 (Sn96.5Ag3.0Cu0.5) solder alloy, bulk; Indium Corporation Indalloy 256 (SAC305) for Preforms product data sheet (Form No. 100346 R0, 2024), selected properties, test temperature not stated; expansion and specific heat from MacDermid Alpha VACULOY SAC TDS (06 September 2023).

Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Is Aluminum 7075-T6 stronger than Solder SAC305?

Aluminum 7075-T6 is stronger: its yield strength is 503 MPa against 22 MPa for Solder SAC305 (22.9x).

Which is lighter, Aluminum 7075-T6 or Solder SAC305?

Aluminum 7075-T6 is lighter: 2,800 kg/m³ against 7,350 kg/m³ for Solder SAC305.

Which is stiffer, Aluminum 7075-T6 or Solder SAC305?

Aluminum 7075-T6 is stiffer: Young's modulus 71 GPa against 6.9 GPa for Solder SAC305, so the same part in Aluminum 7075-T6 deflects less under the same load.

Which is lighter for the same job, Aluminum 7075-T6 or Solder SAC305?

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	Solder SAC305
Stiff rod or tie (tension)	lighter	27x heavier
Stiff beam (bending)	lighter	8.42x heavier
Stiff panel or plate	lighter	5.71x heavier
Strong rod or tie	lighter	60x heavier
Strong beam	lighter	21.1x heavier
Strong panel or plate	lighter	12.6x 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 conducts heat better, Aluminum 7075-T6 or Solder SAC305?

Aluminum 7075-T6 conducts heat better: 130 W/m·K against 61 W/m·K for Solder SAC305.

Which expands less with temperature?

Solder SAC305 expands less: 21.9 µm/m·K against 23.4 µm/m·K for Aluminum 7075-T6.

Among 72 materials

Stiffness against density

Strength against density