Looking for heat conductivity values of CuCrZr in the low temperature range of 4 to 300K

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1. 

   Adam Woodcraft

   June 2, 2011

   For dilute copper alloys, there is an equation which predicts the thermal conductivity from room temperature down to arbitrarily low temperatures.

   I’ve not come across CuCrZr, but a quick web search suggests it may be UNS C18150, with 0.1% zirconium and 1.0% chromium. The equation should work well for this material (it’s not so good when there are much larger amounts of impurity, but should be fine down at least to a room temperature conductivity of 100 W/m/K).

   The excellent Matweb site suggests a room temperature thermal conductivity of 320 W/m/K – see http://www.matweb.com/search DataSheet.aspx?MatGUID=62286b7ce003479c85a4c6b5cab79ae9

   There is a calculator on my web page that applies the conductivity equation: http://reference.lowtemp.org/cucalc.html

   Unfortunately it’s too stupid to be able to work from a room temperature conductivity, but an iterative approach tells me that putting in RRR=4.52 gives a room temperature conductivity of 320 W/m/K (and also gives values all the way down to 1 K) – see
   http://reference.lowtemp.org/rrr_cu.cgi?kappa4k=&RRR=4.52&rhoresid=&lowtemp=1&hightemp=300

   The catch is that since conductivity values converge as temperature increases towards room temperature, there is going to be considerable uncertainty in these values – a change of 1% in room temperature conductivity gives about 5% change at 4 K for this particular room
   temperature conductivity. We don’t know the error in the datasheet values, and of course we don’t know what variation there is between samples for room temperature thermal conductivity anyway.

   At a *guess*, these numbers are good to something like 20%.

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