Mechanism of magnetic recovery in the disorder-order transformation of Fe70Al30 mechanically deformed alloys -: art. no. 212408

The degree of order in Fe-Al intermetallic alloys has an important influence on their magnetic properties. Moreover, the deformation of ordered alloys causes a dramatic increase of magnetization. If deformed alloys are heated, their magnetic properties decrease again. The reordering process was monitored by neutron diffraction, Mossbauer spectroscopy, and calorimetric measurements on the Fe70Al30 crushed alloy. This indicates that the reordering process occurs in two stages. In the first (150-200 degrees C) new small B2 phase domains are nucleated due to vacancy migration. A second reordering stage occurs between 300 and 450 degrees C, where dislocation motion induces B2 domain growth and A2 phase elimination. The main mechanism responsible for this decrease of magnetization during the reordering process is the decrease of the disordered A2 phase content in the alloy.