Nano-crystallization of Fe36Cr12Mo10 phase in Fe55 − xCr18Mo7B16C4Nbx (X = 0, 3, 4) amorphous alloys

Crystallization of nanosize Fe36Cr12Mo10 phase during annealing process of amorphous Fe55 − xCr18Mo7B16C4Nbx (X = 0, 3, 4) alloys and also growth mechanisms were studied by X-ray diffraction and differential scanning calorimetric tests as well as TEM observations. Results of TEM observations showed that Fe36Cr12Mo10 phase crystallized in the structures of the alloys in separated perlitic colonies. Furthermore, it is proposed that Fe36Cr12Mo10 phase crystallized in the alloys in mottled morphology and about average size of 10 nm. In addition, kinetic investigations revealed that not only nucleation frequencies but also growth rates were reduced simultaneously by Nb alloying in the alloys.

► We show the effects of Nb alloying on crystallization process in new kinds of Fe-based amorphous alloys.
► For the first time, we discern the unique morphology of Fe36Cr12Mo10 phase in Fe55 − xCr18Mo7B16C4Nbx (X = 0, 3, 4) alloys.
► We show the effects of Nb addition on decreasing nucleation frequency and growth rate in the alloys.
► Increasing both nucleation and growth activation energies by Nb alloying
► Increasing of the crystallization temperatures and activation energies after Nb addition