Effect of rhenium addition on the strengthening of chromium-alumina composite materials

Chromium alumina composites are well known for their good mechanical properties in comparison to pure ceramics or metals. These composites are characterized by high hardness and high mechanical strength. The aim of the present work was to improve the properties of chromium alumina composites even more and expand the range of their possible applications by addition of rhenium. To achieve this goal, chromium alumina composites containing 2 and 5 vol.% of rhenium were produced via powder metallurgy. The microstructural characterization of the processed material was performed using light microscopy, scanning and transmission electron microscopy as well as X-ray diffraction analysis. Measurement of selected properties such as Young's modulus, bend strength and hardness revealed an advantageous influence of rhenium additions. The results are discussed in terms of the influence of rhenium volume content on the microstructure and on the physical and mechanical properties of the chromium-alumina composites. The solid solution is "only partially formed. The properties strongly depend on the amount and distribution of both aluminium oxide and rhenium content.