Contribution Oral Presentation
KEY DATA FOR SIMULATING THERMAL PROBLEMS - SWIFT MEASUREMENT OF THERMAL DIFFUSIVITY, THERMAL CONDUCTIVITY AND HEAT CAPACITY IN COMPLEX ALLOYS
For the simulation of phase transformations and thermal problems in general, a set of input data is required that for the majority of alloys is unavailable with sufficient accuracy. ”Remedies” are to use data of the pure major alloying element, or use constant values that were measured at room temperature, neglecting their temperature dependence. The effort to gain temperature dependent data for thermal conductivity, thermal diffusivity and heat capacity is considerable, requires several measurement devices and a high degree of expertise. At present it is unlikely that this effort will be undertaken for numerous alloy systems and compositions. At FSU Jena a measurement method is being developed that allows to measure thermal conductivity, thermal diffusivity and heat capacity as a function of temperature in a single experimental run by evaluating transient and steady state temperature profiles. A state-of-the-art infrared camera is used to measure the temperature distribution of a rod-shaped sample in a temperature gradient with high resolution. Transient states are evaluated employing an inverse method to acquire thermal diffusivity, the steady state is evaluated for thermal conductivity and the temperature dependent heat capacity is calculated from these two entities.
The accuracy of the measured data is comparable to those gained by conventional methods. This is demonstrated for Ni and 70:30 brass.