Effects of order-disorder reactions on rapidly quenched Fe-6.5%Si alloy

Deposits of the Fe-6.5wt.% Si alloy rapidly quenched by spray forming were investigated. The order phase can be either B-2 or DO3 depending on annealing treatment conditions. The observation of pairs dislocations indicates the presence of super dislocations and B-2 antiphase boundaries (APBs) which affects significantly the soft magnetic properties. The dislocations bound the APBS which yield delta fringes when image 200 superlattice reflections. Samples treated at 700 degrees C for 1 h were oil quenched, this has induced a decreasing of power loss and the TEM micrographs have showed developed 1/4 < 111 > anti phase domain structure in the B-2 phase. The magnetic properties were: power loss of 1.59 W/kg and coercive force of 76 A/m, at B = 1 T, f = 60 Hz. The samples annealed at 1250 degrees C for 1 h presented the same interaction between the APBs and magnetic properties presenting better power losses. The magnetic properties were: power loss of 1.30 W/kg and coercive force of 40 A/m, at B = 1 T, f = 60 Hz. This suggests a strong interaction between magnetic properties and anti phase domain structure in the B2 ordered phase. Optical microscopy observations corroborate the magnetic measurement conclusions. (C) 2012 Elsevier B. V. All rights reserved.