Discussion in 'Calculations' started by Rutujab, Mar 13, 2013.
Does anyone have any idea about which are best aluminum alloys for heat sink?
"Best" would depend greatly on your particular application and constraints. Here is a excerpt from Wikipedia that should be useful:
The most common heat sink materials are aluminium alloys. Aluminium alloy 1050A has one of the higher thermal conductivity values at 229 W/m•K but is mechanically soft. Aluminium alloys 6061 and 6063 are commonly used, with thermal conductivity values of 166 and 201 W/m•K, respectively. The values depend on the temper of the alloy.
Copper has excellent heat sink properties in terms of its thermal conductivity, corrosion resistance, biofouling resistance, and antimicrobial resistance (see Main Article: Copper in heat exchangers). Copper has around twice the thermal conductivity of aluminium and faster, more efficient heat absorption. Its main applications are in industrial facilities, power plants, solar thermal water systems, HVAC systems, gas water heaters, forced air heating and cooling systems, geothermal heating and cooling, and electronic systems.
Copper is three times as dense and more expensive than aluminium. Copper heat sinks are machined and skived. Another method of manufacture is to solder the fins into the heat sink base. Aluminium can be extruded, but copper can not.
Diamond is another heat sink material, and its thermal conductivity of 2000 W/m•K exceeds copper five-fold. In contrast to metals, where heat is conducted by delocalized electrons, lattice vibrations are responsible for diamond's very high thermal conductivity. For thermal management applications, the outstanding thermal conductivity and diffusivity of diamond is an essential. Nowadays synthetic diamond is used as submounts for high-power integrated circuits and laser diodes.
Composite materials can be used. Examples are a copper-tungsten pseudoalloy, AlSiC (silicon carbide in aluminium matrix), Dymalloy (diamond in copper-silver alloy matrix), and E-Material (beryllium oxide in beryllium matrix). Such materials are often used as substrates for chips, as their thermal expansion coefficient can be matched to ceramics and semiconductors.
Thank you mhjones12. I have read that 6061 & 6063 are commonly used alloys. I wanted to explore if there are any more than that.
I have worked quite extensively with extrusion and would recommend the 6000 series aluminium alloys as they are widely available, can be chosen with reasonable strength if this is an issue (holding threads, for example) and they mostly extrude well. I would also add that the heat dispersal values vary little between these alloys, with better performance probably coming from maximising the surface area of the heat sink and optimising the airflow over it rather than from the alloy choice. Cost is always an issue and these alloys can extrude fine detail if required, whereas some of the 5000 series seem less able in this respect.
You may wish to consider how the heat sink will conform to the hot component to determine the best alloy. If you have a relatively thick heat sink then the more malleable AL alloys may work best for you regardless of their relative degree of thermal conductivity. The tighter you conform to the hot component and the smaller the gap, of course, the better the heat transfer process will go.
We do use ACRA CUT PLATE 6061-T651 TYP 200 ALUM ALOY for Aircraft components
Thank You Steve6br, Mark Stapelton, neves2k9, mhjones12.
All this information, which you guys are sharing is really helpful.
The material issue is just one of many that determine the qualities of a good a heat sink. There are lots of compromises to be made. Not at least the ability to form optimum fins at a convenient price.
Before getting deeper into the subject I would suggest that you use overview calculations to determine how important the material choice is.
Great link Thermal. Thx. (but tried the French site version and they do need a serious translation (or remove simply the Fr language))
My 2 cents: you do not hve to choose in wich mat you will build your sink point right from the start. It depends of the Geo and materials in presence. Usually Al is chosen has it has good extrusion and conductivity characteristics (among others) when you need a heat sink in a small environment.
So it all depends on your requirements (qty, cost, weights, geo etc...)
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