Effect of mechanical milling and sintering on magnetic entropy of Ni-based Ni2CuCrFeAl x (x = 0.5, 1.0, 1.5 and 2.5) high entropy alloys

Abstract

ABSTRACT Nickel-based Ni2CuCrFeAl x (x = 0.5, 1.0, 1.5 and 2.5) high-entropy alloys with good magneto-caloric properties have been successfully prepared by a mechanical milling technique. The phase transformation from FM to PM at the transition point was linear with composition and T c, respectively. Substitution of Al by mechanical milling with subsequent sintering induces a tetragonal distortion in the BCC structure. Prolonged hours of milling followed by sintering result in an increase in magnetic entropy that may result in high refrigeration capacity (RC). Temperature-dependent isothermal magnetization exhibits second-order magnetic phase transition with varying temperature. Moreover, it could be envisaged that distortion occurs in the alloy not only due to the milling effect, but sintering also plays a vital role in achieving large magnetic entropy due to the formation of different intermetallics. This study shows the variation in magnetic entropy of the alloy prepared by mechanical milling followed by sintering at 1073 K.