High Temperature interfacial interactions in CMCs/HEAs (AlCoCrFeNi) systems
VALENZA F. 1, GAMBARO S. 1, FENOCCHIO L. 2, CACCIAMANI G. 1,2
1 CNR-ICMATE National Research Council - Institute of Condensed Matter Chemistry and Technologies for Energy, Genova, Italy; 2 UNIGE-DCCI University of Genova, Chemistry and Industrial Chemistry Department, Genova, Italy
The study of high-temperature interfacial phenomena constitutes a great scientific and technological challenge for those processes that involve liquid metallic phases in contact to ceramics and composites. Applications that foster these studies are joining by brazing, selection of refractories in foundry, and production of metal-reinforced composites or refractory coatings. In particular, the recent introduction of new complex alloys, such as the so-called High Entropy Alloys (HEAs), calls for further studies on this topic.
In this work, such issues are addressed for graphite, SiC and related composites (e.g. SiCf/SiC, Cf/SiC) in contact with liquid AlCoCrFeNi HEAs with addition of refractory elements (W, Ta, Mo) in order to explore the possibility to increase the applicationtemperatures and improve the operating parameters of processes and interfaces involving those materials.
High-temperature sessile drops tests were conducted in the 1400 – 1580 °C temperature range in order to test the wetting and the interfacial reactivity of these materials, also thanks to the experimental characterization of the resulting interfaces.
Moreover, CALPHAD thermodynamic modeling of the involved materials was used to support the interpretation of experimental results and desume interfacial interactions occurred during high temperature wetting tests.