Detailed study of the crystallization behaviour of the metallic glass Fe75Si9B16

The crystallization behaviour of the metallic glass Fe75Si9B16 was studied by means of transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and magnetic measurements. A detailed interpretation of the results led to some interesting conclusions. The material is crystallised in three distinguished steps. During the first step, iron crystallises in two different forms, i.e. pure iron spherulites and Fe(Si) dendrites. High resolution TEM reveals some short-ranged order iron cluster which explains the two morphologies. The primary crystallization follows a homogeneous nucleation and diffusion-controlled three-dimensional growth. The other two steps (i.e. the eutectic crystallization of bcc Fe(Si) and bct Fe3B plus the separation of Fe3B into bcc Fe(Si) and bct Fe2B and the independent crystallization of the bct Fe2B from the amorphous matrix), as one peak in the DSC measurements, follow a homogenous nucleation and interface reaction controlled three-dimensional growth. Finally, a satisfactory coincidence of the DSC and magnetic curves was achieved, something which has to be emphasised, as it is being described for the first time.