Effect of Mo content on glass forming ability and crystallization behavior of Fe-based alloy prepared by atmospheric plasma spraying

Abstract The preparation of Fe-based amorphous alloys has the problems of high cost due to the use of high purity raw materials and low production efficiency of copper mould suction casting. Herein, Fe 75.5-x Cr 4 Si 3.5 P 9.5 B 7.5 Mo x (x=0,1,3,5,7) alloys with a thickness of 100-300 μm were prepared by atmospheric plasma spraying method using industrial raw materials and commercial pure materials as starting materials. The effects of Mo contents on the glass forming ability and crystallization behavior were analyzed. Microstructure and crystallization behavior of as-prepared alloys were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimeter (DSC). The plasma spraying prepared Fe 75.5-x Cr 4 Si 3.5 P 9.5 B 7.5 Mo x with 0 and 5 at% of Mo exhibited fully amorphous alloy features. When Mo content was 5 at%, the crystallization temperature of amorphous alloy increased and the crystallization process changed from one step (amorphous→α-Fe(Si)+Fe 3 B+Fe 2 P) to two steps (amorphous→α-Fe(Mo, Si)→α-Fe(Mo, Si)+Fe 3 B+Fe 2 P), in which the apparent activation energy of crystallization increased from 475 kJ·mol -1 to 542 kJ·mol -1 and 546 kJ·mol -1 . It could be concluded that the enhanced glass forming ability and thermal stability are attributed to the suppression of heterogeneous nucleation by addition optimum amount of Mo. It would provide a basis for the practical application of Fe-based amorphous alloys.