Detection of the liquid–liquid transitions in superalloys melts upon overheating and relaxation by the electromagnetic method

Tyagunov, Andrey; Tyagunov, G. V.; Milder, O. B.; Tarasov, Dmitry

doi:10.1063/5.0027756

Cited by 6 publications

(3 citation statements)

References 44 publications

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“…The composition, structure, and size of clusters, as well as their stability, depend on temperature, and their change is associated with the liquid-liquid structure transition (LLST) [5][6][7][8]. As a result of the LLST, the density, viscosity, electrical resistance, and other macroscopic characteristics of the melt change [7][8][9][10]. After melting the alloy, rapid quenching of the melt follows with the formation of a thin amorphous ribbon, which is a precursor for further heat treatment.…”

Section: Introductionmentioning

confidence: 99%

Melting, Solidification, and Viscosity Properties of Multicomponent Fe-Cu-Nb-Mo-Si-B Alloys with Low Aluminum Addition

Starodubtsev,

Tsepelev,

Konashkov

et al. 2024

Materials

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Melting, solidification, and viscosity properties of multicomponent Fe-Cu-Nb-Mo-Si-B alloys with low aluminum addition (up to 0.42 at.% Al) were studied using an oscillating cup viscometer. It is shown that melting and solidification are divided into two stages with a knee point at 1461 K. The temperature dependences of the liquid fraction between the liquidus and solidus temperatures during melting and solidification are calculated. It has been proven that aluminum accelerates the processes of melting and solidification and leads to an increase in liquidus and solidus temperatures. In the liquid state at temperatures above 1700 K in an alloy with a low aluminum content, the activation energy of viscous flow increases. This growth was associated with the liquid–liquid structure transition, caused by the formation of large clusters based on the metastable Fe23B6 phase. Aluminum atoms attract iron and boron atoms and contribute to the formation of clusters based on the Fe2AlB2 phase and metastable phases of a higher order.

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Section: Introductionmentioning

confidence: 99%

Melting, Solidification, and Viscosity Properties of Multicomponent Fe-Cu-Nb-Mo-Si-B Alloys with Low Aluminum Addition

Starodubtsev,

Tsepelev,

Konashkov

et al. 2024

Materials

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“…Liquid-liquid structure transition (LLST) is accompanied by structural transformations [3]. LLST is revealed as anomalies in the temperature dependence of structurally sensitive properties such as density [4], viscosity [5], electrical resistivity [6], internal friction [7], and magnetization [8]. The discontinuous change in the structure during the heating of the melt is accompanied by an endothermic peak [9] as well as a decrease in the coordination number [10].…”

Section: Introductionmentioning

confidence: 99%

The Activation Energy of Viscous Flow and Liquid–Liquid Structure Transition in Co-B Alloys

Starodubtsev,

Tsepelev,

Konashkov

et al. 2023

Metals

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The temperature dependences of the kinematic viscosity during heating and cooling have been investigated in Co-B melts with a boron content of up to 30.8 at. A liquid–liquid structural transition was found, which is accompanied by an increase in the activation energy and cluster size, as well as a significant decrease in the density of the melt. The liquid–liquid structural transition was associated with the formation of clusters with a short-range order of Co23B6 in the intermediate temperature region. At low and high temperatures, clusters of the order of an atomic size are active participants in the viscous flow. It was shown that with an increase in the cluster size, the activation energy increases and the viscosity of melts decreases. The formation of large Co23B6 clusters during the cooling of melt with low boron content leads to undercooling and the appearance of the transition temperature region with high activation energy, although this region does not exist during the heating stage.

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“…It is believed that the abrupt changes in atomic density and coordination number that occur in certain metal melt in certain temperature ranges [30,[37][38][39] and the subsequent holding of the melt in the range of these temperatures make it possible to affect the crystallizing metal. There is also an assumption that alloying elements are more evenly distributed in the melt with an increase in temperature, due to the irreversible destruction of clusters that results in supercooling of the melt and a change in the structure of the ingots [40,41]. Popel et al [34] investigated the effect of repeated melting of the mother ingot on the thermal stability of a Zr60Al15Ni25 glassy alloy and proposed that the liquid structure, consisting of moving atom clusters, is not homogenous, and one cluster may have a different atomic configuration from another.…”

Section:  Introductionmentioning

confidence: 99%

Effect of thermal treatment of chromium iron melts on the structure and properties of castings

Panichkin¹,

Wieleba²,

Kenzhegulov³

et al. 2023

Mater. Res. Express

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The article describes the results of experimental studies for the effect of thermal treatment (TTM) of G-X300CrMo27-1 high-chromium cast iron samples in the solid-liquid and liquid state on the structure, phase composition and properties of ingots. For ingots with a carbon content of 2.8 to 4.5 wt.%, cooled at a rate of 3.3 * 10-2 deg/s, the dependencies of the structure, phase composition, composition of primary, eutectic carbides and matrix, hardness HV and microhardness of its individual phases and resistance to abrasive wear from the temperature of isothermal holding at TTM. A significant effect of the TTM temperature of melts on the structure and properties of high-chromium cast iron ingots were detected. The temperatures of inflection on the plotted curves for the characteristics of the structure and properties of the ingots were associated with a phase transition in iron at 1400 0С and with a point on the phase diagram liquidus of the Fe-Cr system. This as well as an increase in the concentration of chromium in the composition of primary carbides with an increase in the TTM temperature up to 1480 0С, made it possible to assume that (Cr, Fe)7C3 clusters stable in composition were formed in the melt of such cast irons below 1500 0С. The reasons for the decrease in the size of primary carbides during G-X300CrMo27-1 molten chromium iron overheating above 1500 0С were substantiated based on these data. During the TTM of fine-crystalline ingots made of hypereutectic cast iron in the temperature range between the liquidus and solidus lines, it was detected that the primary carbides (Cr, Fe)7C3 recrystallized resulting in a significant decrease in the chromium content and an increase in the iron content in them. At the same time, their sizes did not change significantly. Their share increased, and the share of eutectic carbides decreased. Such process also had a significant impact on the properties of the resulting ingots. The most preferable temperatures of hot metal cast irons in the liquid and solid-liquid states were identified based on the results of the studies.

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Detection of the liquid–liquid transitions in superalloys melts upon overheating and relaxation by the electromagnetic method

Cited by 6 publications

References 44 publications

Melting, Solidification, and Viscosity Properties of Multicomponent Fe-Cu-Nb-Mo-Si-B Alloys with Low Aluminum Addition

Melting, Solidification, and Viscosity Properties of Multicomponent Fe-Cu-Nb-Mo-Si-B Alloys with Low Aluminum Addition

The Activation Energy of Viscous Flow and Liquid–Liquid Structure Transition in Co-B Alloys

Effect of thermal treatment of chromium iron melts on the structure and properties of castings

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