Aluminum A380 vs. PCB Laminate FR-4

Compare Aluminum A380 vs. PCB Laminate FR-4 strength, stiffness, weight and thermal properties.

Mechanical	Aluminum A380	PCB Laminate FR-4
Yield strength	160MPa1	not given (tensile used)
Ultimate tensile strength	320MPa1	246–385MPa2
Flexural strength	not sourced	531–621MPa2
Elongation at break	3.5%1	not sourced
Young's modulus (stiffness)	71GPa1	21.9–25.8GPa2
Density	2,713kg/m³1	1,920kg/m³341% lighter
Strength to weight	59kN·m/kg	164kN·m/kg2.79x higher
Stiffness to weight	26.2MN·m/kg2.11x higher	12.4MN·m/kg
Poisson's ratio	0.334	0.171–0.1772
Shear modulus	26.7GPa2.63x stiffer in shear	10.2GPa
Bulk modulus	69.6GPa5.71x higher	12.2GPa
Speed of sound	5,116m/s45% faster	3,525m/s

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	Aluminum A380	PCB Laminate FR-4
Thermal conductivity	96.2W/m·K1241x more heat through a fin	0.4W/m·K2
Thermal expansion	21.8µm/m·K1	13–14µm/m·K2
100 mm part over a 50 °C swing	109µm growth	67.5µm growth1.61x less
Specific heat	963J/kg·K1	1,200–1,400J/kg·K3
Heats up and cools (diffusivity)	36.8mm²/s230x faster	0.16mm²/s
Thermal shock resistance	6,669W/m20.6x more resistant	324W/m
Glass transition	not sourced	180°C2
Max service temperature	not sourced	130°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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Sources4 documents: Rheocast Company, Isola, Park Electrochemical (Nelco), North American Die Casting Association

Aluminum A380: A380 aluminium high-pressure die-casting alloy, typical properties; Rheocast Company (aluminium die caster, Germantown WI) A380 alloy data page.
PCB Laminate FR-4: Isola 370HR FR-4 laminate (Polyclad PCL-FR-370HR, 180 C Tg multifunctional epoxy, E-glass fabric), copper removed; Isola data sheet Revision C, last updated April 15, 2021. Woven-glass laminate: the sheet gives in-plane values per weave direction (length / cross) and the Z-axis CTE separately; the solver is isotropic per material.

1
Alloy Aluminum: A380Rheocast CompanyAluminum A380 · Yield strength: typical, 25 °CAluminum A380 · Ultimate tensile strength: typical, 25 °CAluminum A380 · Elongation at break: typicalAluminum A380 · Young's modulus (stiffness): typical, 25 °CAluminum A380 · Density: typical at 68 °FAluminum A380 · Thermal conductivity: typical at 68 °FAluminum A380 · Thermal expansion: typical, 68-572 °F (20-300 °C)Aluminum A380 · Specific heat: typical at 68 °F
2
370HR Laminate and Prepreg Data SheetIsolaarchived copyPCB Laminate FR-4 · Ultimate tensile strength: typical, in-plane: cross direction .. length direction (ASTM D3039)PCB Laminate FR-4 · Flexural strength: typical: cross direction .. length direction (IPC-TM-650 2.4.4B)PCB Laminate FR-4 · Young's modulus (stiffness): typical, in-plane: cross direction .. length direction (ASTM D790-15e2)PCB Laminate FR-4 · Poisson's ratio: typical, in-plane: cross direction .. length directionPCB Laminate FR-4 · Thermal conductivity: typical (ASTM E1952); direction not stated by the sheetPCB Laminate FR-4 · Thermal expansion: typical, in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C)PCB Laminate FR-4 · Glass transition: typical, DSC (IPC-TM-650 2.4.25C)PCB Laminate FR-4 · Max service temperature: UL Relative Thermal Index (UL 796)
3
N4000-6 Laminate Data Sheet (2006)Park Electrochemical (Nelco)archived copyPCB Laminate FR-4 · Density: typical, 50% resin content; another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HRPCB Laminate FR-4 · Specific heat: typical (ASTM E1461); another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR
4
Product Design for Die Casting, Table 4.1: Die Casting Alloys Material Properties ComparisonNorth American Die Casting Associationarchived copyAluminum A380 · Poisson's ratio: typical, as-cast, separately die cast specimens

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 A380 stronger than PCB Laminate FR-4?

PCB Laminate FR-4 is stronger: its tensile strength is 315 MPa against yield strength 160 MPa for Aluminum A380 (1.97x).

Which is lighter, Aluminum A380 or PCB Laminate FR-4?

PCB Laminate FR-4 is lighter: 1,920 kg/m³ against 2,713 kg/m³ for Aluminum A380.

Which is stiffer, Aluminum A380 or PCB Laminate FR-4?

Aluminum A380 is stiffer: Young's modulus 71 GPa against 23.9 GPa for PCB Laminate FR-4, so the same part in Aluminum A380 deflects less under the same load.

Which is lighter for the same job, Aluminum A380 or PCB Laminate FR-4?

For the same stiffness or strength: Aluminum A380 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; PCB Laminate FR-4 is lighter for a strong rod or tie, strong beam, strong panel or plate.

Part that must be	Aluminum A380	PCB Laminate FR-4
Stiff rod or tie (tension)	lighter	2.11x heavier
Stiff beam (bending)	lighter	22% heavier
Stiff panel or plate	lighter	2% heavier
Strong rod or tie	2.79x heavier	lighter
Strong beam	2.22x heavier	lighter
Strong panel or plate	1.98x 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).

Thermal

Which conducts heat better, Aluminum A380 or PCB Laminate FR-4?

Aluminum A380 conducts heat better: 96.2 W/m·K against 0.4 W/m·K for PCB Laminate FR-4.

Which expands less with temperature?

PCB Laminate FR-4 expands less: 13.5 µm/m·K against 21.8 µm/m·K for Aluminum A380.