Study of microstructure and properties of in-situ alloyed AlCoCrFeNi(Y) high-entropy alloy by laser directed energy deposition method

In this study, the equimolar AlCoCrFeNi(Y) high entropy alloy (HEA) was obtained through in-situ alloying by laser directed energy deposition (DED) method. The in-situ alloying route was designed to be economical and flexible such that a commercial cobalt-rich powder for thermal spray applications was used as the base powder, supplemented with additional elemental Al, Fe, Cr and Ni powders. For the obtained AlCoCrFeNi(Y) HEA, two phases of cubic crystal structures were identified which are Pm $(3) over bar $ m (221) ordered B2 and Im<$(3)ver bar $>m (229) disordered A2 BCC structures. Morphology of the resultant material was dominated by dendritic microstructure. Elongated grains with an average area of 327.1 mu m(2) growing in zigzag pattern along the deposition direction were observed. The average microhardness was measured to be 635.6 HV0.5. More importantly, the presence of twin boundaries was identified by the peaks in grain misorientation angle distribution at 39 degrees and 60 degrees. The crystallographic study also discovered fiber texture with 45 degrees twist from < 100 > direction. In addition, the findings about microstructure, texture and microhardness of AlCoCrFeNi(Y) sample were compared with the results obtained by literature studies on similar HEAs, and the differences were analysed and discussed. (c) 2022 Society of Manufacturing Engineers (SME). Published by Elsevier Ltd. All rights reserved.