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Abstract The present work deals with the synthesis and evaluation of the microstructural and mechanical properties of face-centred cubic Ni 1.5 Co 1.5 CrFeTi 0.5 high-entropy alloy strengthened by nano-sized titanium oxide dispersion and coherent precipitates of Ni 3 Ti intermetallic phase produced by powder metallurgy. The alloy's properties are well tuneable by the use of proper heat treatment. The alloy exhibits an excellent combination of tensile strength and ductility, reaching an ultimate tensile strength of 1460 MPa and elongation of 14.5% in solution annealed state and 1660 MPa and 4.8% in the aged condition. Most of the strengthening contribution was attributed to Orowan-type strengthening mechanism. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

The present work is focused on synthesis and mechanical properties evaluation of non-equiatomic Ni 1,5 Co 1,5 CrFeTi 0,5, ductile single phase high entropy alloy (HEA) with excellent mechanical properties (bend strength R mb = 2593 MPa, tensile strength R m = 1384 MPa, tensile elongation to fracture of 4.01%, and elastic modulus of 216 GPa) surpassing those of traditional as-cast HEA. For the alloy production, a combination of mechanical alloying (MA) process in a planetary ball mill and spark plasma sintering (SPS) for powder densification was utilized. The tensile properties of a bulk material produced by a combination of MA + SPS are characterized for the first time. The feedstock powder and corresponding bulk material microstructure, elemental and phase composition, and mechanical properties were investigated by scanning (SEM) and transmission (TEM) electron microscopy, energy-dispersive X-ray spectroscopy (EDX), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), as well as impulse excitation of vibration, Vickers microhardness and tensile and bend strength tests, respectively. The structure of the samples consisted of single-phase FCC high entropy solid solution of extremely fine-twinned grains and oxide inclusions inherited from the original powder feedstock. Dimple-like morphology corresponding to ductile fracture mode has been observed on the fracture surfaces, with crack initiation sites on the inclusions phases. [ABSTRACT FROM AUTHOR]