EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

One of the most interesting characteristics of the high entropy alloys (HEAs) is that they form a solid solution which lattice with a high distortion resulting in a low diffusion coefficient and an impediment to sliding of dislocations. These alloys have more than 4 principal elements, which increases the entropy of the system and increases the solubility between them, promoting the formation of a simple solid solution. The characteristics of the solid solution together with a high entropy give rise to alloys with high stability, hardness and strength, also at high temperatures.
But, do all HEA compositions result in the formation of a simple solid solution? No, there are several studies that state empirical rules based on the characteristics of the involved elements that predict phase formation with high reliability. However, to be successful in the formation of the desired phase and, therefore, in the expected properties, it is necessary to know how the conditions applied during the processing of the alloy affect the final microstructure.
In this work, the FeCoNiCrAl1.8Cu0.5 alloy has been processed, whose composition has been designed taking into account the empirical rules published in the literature to obtain a simple BCC phase. Two consolidation techniques have been chosen from the group of electric current assisted sintering (ECAS) methods: Spark Plasma Sintering (SPS) and ERS (Electric Resistance Sintering).
ERS is a novel technique that allows a very fast consolidation thanks to the application of high current density that could reduce one of the processing problems in HEA: the elements segregation. The comparison of the microstructures obtained by a fast processing technique and a very fast processing technique will allow to know how the physical characteristics of the processing influence the phase formation and the final properties of the alloy.