Metallographic Preparation of Single Powder Particles

Abstract

Abstract This work developed a systematic method for a metallographic preparation of single powder particles with diameters of approx. 20 to 40 μm. It was motivated by the objective of understanding additive manufacturing processes such as Laser Powder Bed Fusion. A fundamental aspect of the relationship between manufacturing, structure, and properties is the correlation of rapid solidification and resulting microstructure. During powder-based additive manufacturing processes, cooling rates up to 1 MK/s are attained. A thermal analysis determining the characteristics of solidification at such rapid cooling rates can be performed with the aid of chip sensor-based, dynamic Differential Fast Scanning Calorimetry, DFSC. For this purpose, the heat flow during the solidification of single powder particles is measured and, for instance, the solidification onset temperature is evaluated as a function of cooling rate. It is thus possible to estimate the undercooling which has a significant impact on the resulting structure. Subsequently, cross sections of single powder particles must be prepared for the analysis of the resulting structure.