Non-isothermal crystallization kinetics of a Fe–Cr–Mo–B–C amorphous powder

Publication date: 15 May 2020Source: Journal of Alloys and Compounds, Volume 823Author(s): Q. Dong, P. Song, J. Tan, X.M. Qin, C.J. Li, P. Gao, Z.X. Feng, M. Calin, J. EckertAbstractFe–Cr–Mo–B–C amorphous powders are usually used in thermal spraying, spark plasma sintering or 3D printing to prepare coatings or large-sized bulk amorphous alloys. However, their non-isothermal crystallization kinetics is far from being investigated in detail because of their relatively complicated crystallization behavior. In this work, the phase evolution, crystallization kinetics and crystallization mechanism of Fe–Cr–Mo–B–C (Cr: 25–27 wt%, Mo: 16–18 wt%, B: 2–2.2 wt%, C: 2–2.5 wt%) amorphous powder during non-isothermal crystallization are analyzed by X-ray diffraction, scanning electron microscope and differential scanning calorimetry together with Ozawa method and local Avrami exponent. The peak temperature of the first precipitated phase is less sensitive to the heating rate. In the non-isothermal crystallization process upon constant-rate heating to elevated temperatures the phase sequence is: α-Fe, M23(C, B)6, M7C3 and FeMo2B2 (M = Fe, Cr, Mo). The apparent activation energy of crystallization of the amorphous powders obtained using Kissinger’s method is between 385 and 557 kJ/mol, which is higher than that of most iron-based amorphous alloys reported so far, indicating a relatively high stability against crystallization. a-Fe and FeMo2B2 have a similar ...

Source: Journal of Alloys and Compounds - January 18, 2020 Category: Chemistry Source Type: research