A novel low-density semi-hard magnetic Al20Fe20Mg20Ni20Ti20 high entropy alloy

A relatively low density nanocrystalline high entropy alloy (HEA) with a nominal composition of Al20Fe20Mg20Ni20Ti20 is synthesized through the mechanical alloying process. The synthesized HEA is comprised of the mixture of bcc and fcc solid solution with crystallite size of the order of 6 to 7 nm. To understand the phase stability, the synthesized HEA is annealed at 200 degrees C and 500 degrees C for 2 hr. The 200 degrees C annealed HEA does not show any significant change in the XRD pattern. However, annealing at 500 degrees C affects the relative volume fraction of the formed phases. The synthesized Al20Fe20Mg20Ni20Ti20 HEA showed better magnetic characteristics with Ms (54.28 emu/g) and Hc (43.4 Oe) as compared to the many of recently reported HEAs. Moreover, for 200 degrees C annealed HEA, the found value of Ms (54.92 emu/g) and Hc (42.4 Oe) is similar to the as-synthesized HEA. An interesting change in magnetic behaviour has been observed after annealing at 500 degrees C, which may be related to the change in the fcc to bcc phase volume and change in the lattice parameter of these phases.