LFA 1000 – Steel alloys – Thermal conductivity / thermal diffusivity / specific heat
Steel alloys – Thermal conductivity – thermal diffusivity – specific heat
Steel alloys are very sensitive to the material composition which results in significant changes in the mechanical and thermal properties. This should improve the properties, so that the alloys can be used for highly-demanding applications where pure steel fails. Examples are nuclear reactors, railways and turbine blades of jet engines. In general steel alloys have a broad range of application, including pipes, automotive transport, energy and machinery.
The measurement above shows the measurement of the thermal diffusivity by LFA 1000. In the same measurement cycle also the specific heat capacity was measured by a comparative method using stainless steel as a reference.
Using these values and the density of the sample, the thermal conductivity can be determined. The thermal diffusivity and thermal conductivity decrease with higher temperatures, whereas the specific heat capacity firstly slightly decreases and then increases with temperatures higher than 200 °C.
The same measurement was done for another steel alloy (Sample 2). Here Inconel was used as a reference for the determination of the specific heat capacity. The following diagram shows the thermal conductivity of the sample from above (Sample 1) and the other steel alloy (Sample 2).
The diagram clearly shows that steel alloys can behave completely different due to different compositions. The thermal conductivity of Sample 1 decreases with temperature and Sample 2 shows an increasing thermal conductivity for higher temperatures.