Conferences

NEW METASTABLE TERNARY Fe7.5MoC1.5 PHASE: NANOSIZED STATE AND Mn-Like polymorphism

 
М.V.Graivoronskii,
 
A.М.Zaslavskii,
 
М.V.Кіndrachuk
 

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Krzhizhanovsky str., 3, Kyiv, 03142, Ukraine
Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2018, #07/08
http://www.materials.kiev.ua/article/2637

Abstract

The Fe–Mo–C spinning ribbons produced by rapid melt cooling at a rate of ~ 106 K/sec have been studied by transmission electron microscopy. The metastable ternary phase of stoichiometry close to Fe7.5MoC1.5 has been found for the first time. Under conditions far from equilibrium, this phase behaves like a metallochemical and structural analog of elementary Mn under thermodynamic equilibrium conditions, namely: it can appear in crystalline structures, isostructural to γ-, β-, and α-polymorphous modifications of Mn (γ, π, and χ phases, respectively). In addition, the temperature sequence of diffusionless γ → π → χ transformations in the cooling process is similar to the temperature sequence of αpolymorphic γ → β → transformations of Mn. In this case, the γ → π transformation has the features of a martensitic analog, and the temperature of the π → χ-transformation of nanosized metastable phases is close to the temperature of the polymorphic β-Mn ⇄ α-Mn transformation. It is shown that the crystal lattices of the π and γ phases obey orientation relationships, for example: (110[2 ‾2 1]π║(101)γ[0 ‾1 0]γ.


FE–MO–C SYSTEM, MN-LIKE POLYMORPHISM, NANOSIZED PHASES, ORIENTATION RELATIONSHIPS