Synthesis and Magnetic Properties of Fe₂CrSi Heusler Alloys by Mechanical Alloying

We have applied mechanical alloying (MA) to prepare nanocrystalline Fe₂CrSi Heusler alloy using a mixture of elemental Fe₅₀Cr₂₅Si₂₅ powders. Its structural characterizaion and magnetic properties have been studied by X-ray diffraction, differential scanning calorimeter and vibrating sample magnetometer measurements. α-(Fe,Cr,Si) BCC phases coupled with amorphous phase are obtained after 40 hours of MA. The saturation magnetization (Ms) of MA powders decreases with MA time due to the magnetic dilution by alloying with nonmagnetic Cr and Si elements. A Fe₂CrSi Heusler alloy can be synthesized by MA for 40 h coupled with subsequent heat treatment. X-ray diffraction result shows that the average grain size of Fe₂CrSi Heusler alloys prepared by MA for 40 h and heat treatment at 500 °C is in the range of 88 nm. Ms of MA powders after heat treatment at 500 °C and 650 °C are found to be 63 emu/g and 79 emu/g, respectively. Ms of Fe₂CrSi Heusler alloys by MA in this study is low value compared with other Fe-based Heusler alloys, probably being attributed to the formation of nonmagnetic Cr3Si phase with further annealing.