Microstructure Tomography – An Essential Tool to Understand 3D Microstructures and Degradation Effects

Abstract

In materials science the 3D morphology of the structure is the key to understand the relationships between the manufacturing parameters and the properties of the material. The question is at which conditions two-dimensional characterization and the application of the stereological relations can provide sufficient information and when 3D analysis is indispensible or offers additional insights. Correct description of the 3D grain (particle, pore, object, etc.) size distribution is one of the most important requirements for the microstructure characterization. Taking this problem as an example it will be shown for which grain shapes 2D image analysis with stereological estimates delivers reliable results for the 3D situation and when the microstructural tomography is absolutely necessary. The problem will be discussed assuming grain shapes of different complexity (sphere – equiaxial polyhedra – non-equiaxial polyhedra – non-convex grain shapes).

It will be shown that the 3D characterization of non-convex, irregular and interconnected grains is absolutely indispensable in order to quantify spatial parameters, like connectivity or particles density. Growth mechanisms will be characterized using euclidic distance transformation. A detailed 3D image analysis and simulations enable the comprehensive quantitative evaluation of local microstructure degradation effects.