Coercivity relaxation in mechanically alloyed amorphous Fe50 B50 samples

Samples of composition Fe₅₀B₅₀ have been prepared by high energy ball milling. The phase distribution of the as-milled material included a majority amorphous phase, although that distribution depended on the degree of mechanical hardness of the balls used during the preparation process (crystalline phases were detected in the samples alloyed using regular, non-hardened balls). The hysteretic properties depended also on the type of balls used, the as-milled coercive force being smaller in the case of the samples prepared with harder balls. The measurement of this parameter in samples prepared using non-hardened balls and submitted to thermal treatments evidenced the possibility of reducing significantly the as-milled coercive force. The observation of the same phase distribution (and average grain size of the crystalline phase) present in both the as-milled and the annealed samples led us to conclude that a combination of stress relaxation and of improvement of the interphase coupling could be responsible for the enhancement of the soft properties of the samples resulting from the treatments