Several composites, consisting of a metastable austenitic steel matrix and varying amounts of MgO partially stabilized zirconia particles (Mg‐PSZ), were produced through spark plasma sintering (SPS). Compression tests were carried out at room temperature in a wide range of strain rate (4 · 10−4 s−1, 2 · 10−3 s−1, 10−1 s−1, 1 s−1, 102 s−1). In conjunction with subsequent microstructural investigations, the mechanical material behaviour was clarified. All composites showed a good ductility and a high strength. The strength increased with an increase of the ceramic content and with higher strain rates. Both, the martensitic transformation of the steel matrix and of the ceramic particles, could be proved at all strain rates. In this study no significant influence of the strain rate on the amount of transformed ceramic could be detected while the steel matrix showed less α′‐martensite after compression at rising strain rates. Local material failure occurred around 0.3 true compressive strain depending on the applied strain rate and the amount of the Mg‐PSZ powder. The main reason for the damage is the relatively weak ceramic‐ceramic interface within the ceramic clusters.

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Micro computed tomography (μCT) is proposed as a tool for the characterization of powders. Using this technique three dimensional images carrying the whole spatial information on a particular powder can be obtained. After an image analytic separation of the single particles, distributions of geometric characteristics describing size, shape, and spatial arrangement of the particles can be estimated. The method is applied to four samples of powders with different particle structure. The results are compared with particle size characteristics measured by laser diffraction, sieve analysis, and the analysis of microscopic 2D images.

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