As-Cast Microstructures of High Entropy Alloys Designed to Be TaC-Strengthened

In this work two new alloys were obtained by extrapolation from a wellknown high entropy alloy, the equimolar CoNiFeMnCr one. This was doneby addition of carbon and tantalum, Ta being one strongestMC-former elements. They produced conventional casting underinert atmosphere. The microstructures characterized X-raydiffraction, metallography, electron microscopy, energy dispersionspectrometry. Their hardness also measured indentation.In parallel, original alloy synthesized andcharacterized for comparison. reference HEA is single-phasedwith an austenitic structure, while {Ta, C}-added aredouble-phased, with matrix interdendritic script-likeTaC carbides. matrixes these HEA/TaC are equivalent toan to which 2 wt.% present in solidsolution. presence TaC carbides caused significant increase inhardness suggests that may be mechanicallystronger than at temperature.