Nanocrystalline FeAl intermetallics obtained in mechanically alloyed Fe_(50)AL_(40)NI(10) powder

摘要

B2-Fe_(47)Al_(53) intermetallics has been produced by mechanical alloying in a planetary ball mill, using elemental Fe, Al and Ni powder mixture. The microstructural and magnetic properties of the mechanically alloyed Fe_(50)AL_(40)NI(10) powdered samples were investigated by X-ray diffraction and ~(57)Fe Mossbauer spectrometry at 300 and 77 K. As resulted from the X-ray diffraction studies, the ordered B2 structure was formed in the Fe_(50)AL_(40)NI(10) powder, together with the bcc a1-Fe(Al, Ni) (i=1,2) solid solutions. Further milling led to a partial disordering of B2-Fe_(47)Al_(53); it has undergone an order-disorder transition which is characterized by an expansion of the volume (lattice disorder) and a magnetic transition from the paramagnetic to ferromagnetic state which is characterized by strong ferromagnetic interactions in the alloy. The nano-crystalline bcc a_i-Fe(AI, Ni) solid solution was ferromagnetic with a mean crystallite size of 6 nm.