Thermal Conductivity of Aluminium
| Value | 237 W/(m·K) |
| Status | Measured: ± 5 W/(m·K) (0.021 relative) |
| Source | ASM Handbook, Vol. 2: Properties of Nonferrous Alloys |
| Categories | Material PropertiesEngineering & Trade |
| milliwatt per meter-kelvin | 237,000 mW/(m·K) |
| BTU inch per hour square foot Fahrenheit | 1,643.2328 BTU·in/(h·ft²·°F) |
| watt per meter-kelvin | 237 W/(m·K) |
| watt per meter-Celsius | 237 W/(m·°C) |
| kilocalorie per hour meter Celsius | 203.91969 kcal/(h·m·°C) |
| BTU per hour-foot-Fahrenheit | 136.93607 BTU/(h·ft·°F) |
| watt per centimeter-kelvin | 2.37 W/(cm·K) |
| calorie per second centimeter Celsius | 0.56644359 cal/(s·cm·°C) |
| kilowatt per meter-kelvin | 0.237 kW/(m·K) |
Learning zone
Pure aluminium conducts about 59 % as well as copper but at a third of the density, so per unit of mass it is the better conductor — the reason heat sinks, radiators and overhead transmission conductors are aluminium. The alloying penalty is severe and routinely overlooked: 6061-T6, the structural workhorse, manages only 167 W/(m·K), and 7075-T6 about 130. Extruded heat sinks are usually 6063, chosen partly because it retains around 200 W/(m·K).
Temper matters too, because it changes how much solute is in solution versus precipitated: 6061 in the T4 temper conducts less than in T6. Take 237 as pure metal at room temperature and use the alloy datasheet for anything real. In fin design the conductivity mostly sets the fin efficiency — beyond a certain thickness-to-length ratio, extra conductivity buys almost nothing, and the convective film coefficient is what limits the heat sink.