FIB tomography of WC-Co composites

Abstract

The development of new methods of materials inspection allows a visualization and characterization of materials, increasingly accurate. So far, observation, characterization and study of materials were carried out using two-dimensional projections and images, which offer only a partial view of reality. A recent 3D-microscopy method, focused ion beam (FIB) tomography, has been used to characterize different tungsten carbide – cobalt samples. With this method, high resolution images of the entire internal volume can be obtained, which has been used to threedimensional reconstruction of microstructure of carbides and binder, allowing the characterization of material as is, avoiding the lack of information of two-dimensional projections. This 3D-data can also be used for finite element simulations, in order to understand and correct the mathematical models currently used for micro-mechanical analysis of the material. Thus, the aim of this project is to describe a method for obtaining and reconstruction of the microstructures and its analysis; comparing obtained 3D-data with information based on two-dimensional methods appeared in the literature and analysing its reliability and applicability. For that, three different WC-Co grades were analysed. This described technique has proved to be a reliable method to characterise and analyse the real material as is. Obtained results from three-dimensional analysis are coherent with reported values in the literature. Also, a new parameter, skeleton density of binder phase ( ), is described, and parameters difficult to obtain by two-dimensional analysis, like interphase area or specific surface area can be measured directly from three-dimensional reconstruction.