Grain growth and texture in rapidly solidified Fe(Si) 6.5 wt% ribbons

The dependence of structural properties of Fe(Si) 6.5 wt.% ribbons on annealing treatments has been investigated in the temperature range 700-1300 degrees C. Two different annealing methods, respectively characterized by slow (conventional) and fast (infrared) heating rate, have been considered. It is found that abnormal grain growth takes place above a threshold temperature, which depends on the type of annealing, with the average grain size attaining a maximum value around 200 mu m. Such a growth is conducive to a cube-on-face (100) crystallographic texture after conventional annealing, whereas after the infrared treatment a cube-on-edge (110) texture is observed. The texture development is here discussed in terms of competition between grain boundary and surface energy minimization, with attention devoted to the role of the presence of oxygen on the surface energy of (100) and (110) crystallographic planes. (C) 1997 Elsevier Science S.A.