Devitrification of Fe-Based Amorphous Metal SAM 1651 and the Effect of Heat-Treatment on Corrosion Behavior

Devitrification of amorphous alloys is a process in which thermodynamically preferable crystalline phases form from the metastable amorphous phase. The corrosion behavior of the crystalline phases and the remaining amorphous material is likely to be different from that of the fully amorphous material and could have detrimental effects on the corrosion resistance of the devitrified material. The effect of heat-treatment on the corrosion behavior of an Fe-based bulk metallic glass Fe48Cr15Mo14C15B6Y2 [structural amorphous metal (SAM) 1651] was examined, which revealed a degradation in the corrosion resistance of SAM 1651 upon annealing at 700 degrees C. However, the partially devitrified material still exhibited good corrosion resistance even in the highly aggressive environments of 6 M HCl. The preferential corrosion sites of nanoscale in both fully amorphous and partially devitrified materials were identified with transmission electron microscope analysis. The corrosion resistance of both fully amorphous and partially devitrified materials was explained in terms of chemical and structural characteristics of the alloys.