Determination of temperature dependent thermophysical properties using an inverse method and an infrared line camera

Temperature dependent thermal diffusivities of two alloys (Al-4 wt.% Cu and 70:30 α-brass) are determined using a one-dimensional inverse method that is based on a least-square scheme. Transient temperature histories required as input for the proposed inverse method are recorded using an infrared line camera during one-sided heating or cooling. An aerogel that is transparent for infrared radiation is used as insulation material, ensuring that heat conduction is essentially one-dimensional. Temperature profiles along the samples are obtained using up to 512 photo diodes as temperature sensors. Temperature dependent specific heat capacities of the Al-Cu alloy and brass, calculated using a thermochemical library based on the CALPHAD method, are employed to calculated thermal conductivities. The calculated thermal conductivities are in good agreement with literature values. It is shown that the combination of the numerical calculations and the heating experiments provides an efficient way to determine temperature dependent thermophysical properties of alloys.