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

Abstract

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.

Evolution of material properties during the sintering process of Cr-Re-Al2O3 composites

“…The reported phenomenon is related to the effect of rhenium dissolution in the structure. As confirmed in the previous research reported by Chmielewski et al [15], rhenium dissolves in chromium and acts stronger as a solid solution. Therefore, the increase in sintering time leads to an increase of Young's modulus and hardness due to a better dissolution of rhenium and better homogenization of the structure due to extended sintering time.…”

“…rhenium or nickel) is added to the chromium matrix [14]. As reported before [15,16], the main issue related to manufacturing of this material is to obtain a uniform distribution of components in volume structure. Rhenium as a small amount partially reacts with chromium and after the sintering process chromiumrhenium solid solution is detected, but also chromium and rhenium phases separately [17].…”

Rhenium doped chromium–alumina composites for high-temperature applications

“…The present paper is focused on the development of novel Cr/Re/Al 2 This work further extends the authors' recent research efforts on bulk Cr/Re/Al 2 O 3 composites reported in [14][15][16] and contains preliminary results for Cr/Re/Al 2 O 3 composite coatings.…”

“…Table 1) Rhenium was detected in all chromium grains, although its concentration on individual chromium grains was fluctuating [15]. This effect is to be traced back to the difference between the Cr and Re grain sizes and too short sintering time to allow for the completion of the solid state reaction throughout the whole specimen volume.…”

Metal-ceramic functionally graded materials – manufacturing, characterization, application

“…In addition, the properties of these materials can be enhanced by doping a metallic matrix with a low amount of rhenium [12]. Because of its unique properties, rhenium is used in industry as an additive to metal alloys which significantly improves their hardness and resistance to corrosion.…”