Deformation mechanisms and failure behavior of binder jetting manufactured AlCoCrFeNi high-entropy alloy

This study investigates the deformation mechanisms and failure behavior of the high-entropy alloy (HEA) AlCoCrFeNi, fabricated via binder jetting and subjected to various heat treatments. The alloy’s microstructure is analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD), while the deformation mechanisms are probed through macro- and nano-indentation testing. The results reveal several novel insights: (i) second-stage heat treatments significantly alter the morphology of nanoprecipitates within the B2 matrix, (ii) the FCC/B2 interphase at grain boundaries influence intergranular deformation, (iii) aging treatments activate greater slip and shear band formation enhancing hardness and toughness, and (iv) sigma-phase precipitates formed by spinodal decomposition promotes transgranular failure. Collectively, these findings offer a mechanistic basis for tailoring failure resistance in AlCoCrFeNi HEAs via optimized multi-stage heat treatment strategies, thereby advancing their mechanical reliability in demanding applications.