Metastable States and Properties of Fe–Be Alloys Quenched from Liquid State
V. F. Bashev, S. I. Ryabtsev, O. I. Kushnerov, N. A. Kutseva, A. A. Kostina
Oles Honchar Dnipro National University, 72 Gagarin Ave., UA-49010 Dnipro, Ukraine
Received: 12.04.2019; final version - 13.12.2020. Download: PDF
The nonequilibrium quenching from a melt during the process of splat cooling can be provide a practical solution for the formation of metastable structure with a necessary set of improved physical properties of films. The formation of metastable mixture phases, $i.e.$ highly supersaturated substitution solid solution (up to 30.5 at.% beryllium) based on the Fe–Be alloy and extended congruent FeBe$_2$ phase, is revealed by the method of quenching from the liquid state (QLS). The used in the work cooling rate ($\sim$10$^8$ K/s) of eutectic and near-eutectic compositions melts, which is usually sufficient to form a solid amorphous state in the structure of rapidly cooled alloys, in a case of Fe–Be eutectic alloy even with a deep temperature eutectic (the slope of the liquidus lines is $\sim$10 deg/at.%) cannot prevent the processes of nonequilibrium crystallization of the melt. On the base of X-ray diffraction data it is experimentally confirmed that initial congruent FeBe$_2$ phase leads to eutectic crystallization: $\alpha$-Fe + FeBe$_2$. The diffraction profiles of lines of these phases indirectly certificate about this. As shown, the method QLS allows to widen region of existing metastable solid solution from 0.5 to 30.5 at.% Be. The grades of supercooling (a few hundred degrees) at this rate of cooling are sufficient for the nonequilibrium formation of the film structure. The positive role of the QLS method in increasing of the level of mechanical and hard-magnetic characteristics in rapidly quenched Fe–Be films is shown. For QLS-films Fe–36%Ве the magnitude of microhardness is 5 times more than for casting ones.
Key words: splat quenching, highly supersaturated solid solution, congruent phase, eutectic reaction, microhardness, coercivity.
PACS: 61.43.Dq, 62.20.Qp, 64.60.My, 75.50.Cc, 81.30.Bx, 81.40.Ef, 81.40.Rs
Citation: V. F. Bashev, S. I. Ryabtsev, O. I. Kushnerov, N. A. Kutseva, and A. A. Kostina, Metastable States and Properties of Fe–Be Alloys Quenched from Liquid State, Metallofiz. Noveishie Tekhnol., 43, No. 2: 245—254 (2021) (in Ukrainian)