High performance thermal link with small spring constant for cryogenic applications

摘要

We developed a soft and high thermal conductive thermal link for cryogenic applications. The measured maximum thermal conductivity was approximately 18500 W/m/K at 10 K. This spring constant was 1/43 of that of a single thick wire with the same cross-sectional area at room temperature. We reached these performances by utilizing high purity aluminum (99.9999%, 6 N) and by stranding many thin wires that are 0.15 mm in diameter. The electrical Residual Resistivity Ratio was also measured and used to estimate the thermal conductivity by the Wiedemann-Franz law. We observed the size effect on the electrical conductivity, and evaluated the effect of mechanical deformation to the RRR. These evaluations allow us to design a pragmatic thermal link for cryogenic application.