Metastable primary precipitation phases in multicomponent glass forming Fe-base alloys with metalloids

Structure transformations at the initial stages of devitrification have been investigated for alloys with good glass forming ability on the base of Fe-B-Si, Fe-P-C, Fe-P-B-C systems with various additions. Systematization of the metastable phases formed in these alloys showed that: (a) metastable phases at the initial stages of crystallization are tetrahedrally close packed (TCP) or aperiodic structures and possess compositions close to the mean composition of the alloy; (b) the observed TCP phases belong to one family of structures related to α-Mn for essentially different types of alloying systems, having in common a high glass forming ability; (с) for alloys based on the same system with different small alloying additions, structure of the metastable phase can change within this family of related phases. The obtained results show that Fe-based metallic glasses with metalloids are not essentially different from metal-metal type glasses.