Abstract:
AlCoCrFeNi high entropy alloy (HEA) was synthesized by mechanical alloying (MA). Formation of single-phase solid solution of body centered cubic (BCC) structure (a = 2.88 ± 0.01 Å) was confirmed from x-ray diffraction (XRD) and high-resolution synchrotron XRD. The nanostructure nature of the milled powder was observed through transmission electron microscopy (TEM). The milled powder was consolidated through conventional sintering at 900 °C (1173 K) for 2 h. The microstructure of the sintered AlCoCrFeNi HEA showed two types of grain distribution. Coarser size of grains varied in the range of ∼18–22 μm and finer grains of ∼ 2–10 μm sizes that are homogeneously distributed in the matrix. Detailed analysis of the x-ray diffraction pattern of sintered HEA showed the phase transition from parent BCC phase to Al–Ni type B2 phase (cP2) (a = 2.91 ± 0.02 Å) and Ni3Al type L12 phase (cP4) (a = 3.56 ± 0.01 Å) along with Co–Cr type σ phase (tP30) (a = 8.8 Å, c = 4.53 Å). The sintered samples showed high value of microhardness, i.e. 919 ± 18 HV at 300 g load. Alloy shows fascinating soft magnetic property with saturation magnetization of 70.05 A m2/kg (emu/gm) along with effective Curie temperature (TC) of ∼617 °C (890 K). © 2020 Elsevier B.V.
