Thermophysical property measurements at high-temperatures for power engineering and additive manufacturing processes

Abstract

To address the needs for increasing efficiency in power conversion, stratified structures like thermal barrier coatings, are used to increase operation temperature. Also advanced material processing like 3D laser printing of metals and ceramics are based on a layer-to-layer process at high temperatures, resulting in non-homogeneous components. Both systems require more and more detailed investigation methods to characterise the material properties of the resulting structures and to optimize the relevant processes. To address the required needs in advanced material characterisation recently an attempt was started to develop a unique measurement set-up for advanced material characterisation. This method is based on the well know laser flash principle, which was improved by adding supplementary heating sources and additional detection channels. Combining different heating mechanism and heating times with the two-dimensional measuring of the thermal flow across the sample enables the determination of different opto-thermal parameters and other material properties, e.g. mechanical contact, electrical conductivity or optical data, which also depend on or affect the flow of heat. In this paper we describe the implementation of the different optical methods to measure the thermal heat flow by point-like and two-dimensional temperature measurement and present first results on several samples.

Opto-Thermal Investigation of Additively Manufactured Steel Samples as a Function of the Hatch Distance

“…The opto-thermal evaluation was carried out with a laser flash apparatus (NETZSCH LFA 427), which is commonly used to measure the thermal diffusivity of a variety of different materials [ 15 ]. In this method, a short laser pulse at the front side heats a plane-parallel sample and the resulting temperature rise at the sample backside is measured.…”