Heat transfer-solidification kinetics modeling of solidification of castings

Stefanescu, Doru M.; Upadhya, G.; Bandyopadhyay, Dilip Kumar

doi:10.1007/bf02656584

Cited by 121 publications

(51 citation statements)

References 5 publications

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“…As shown in Figure 17 for Bi-Sb10 alloy [65], as the TL of Bi-Sb10 is 346 °C, the nucleation under-cooling increases from 13.1 °C of the procedure A to 18.9 °C of the procedure B. Figure 18 shows the solidification rate curves of Bi-Sb10, dfS/dt-t, obtained by Newton Thermal Analysis (NTA) method [66], here dfS/dt indicates the solid fraction fS increased in unit time. According to Kurz' theory [67], the altitude of the first peak on dfS/dt-t curve betokens the level of nucleation rate, the apparently enhanced peak of dfS/dt-t for the sample with procedure B signifies a quite higher nucleation rate.…”

Section: The Effects Of Ti-llst On Solidification Behaviors and Strucmentioning

confidence: 99%

Temperature-Induced Liquid-Liquid Transition in Metallic Melts: A Brief Review on the New Physical Phenomenon

2015

Metals

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Understanding the nature of liquid structures and properties remains an open problem for many fundamental and applied fields. It is well known that there is no other defined phase line above liquidus (TL) in phase diagrams of ordinary alloys. However, via resorts of internal friction, electric resistivity, thermal analysis, X-ray diffraction, solidification, etc., the results of our research on lots of single-and multiple-component melts show a novel physical image: temperature induced liquid-liquid structure transition (TI-LLST) can occur above TL. Moreover, the solidification behaviors and structures out of the melts that experienced TI-LLST are distinct from those out of the melts before TI-LLST. In this paper, some typical examples of TI-LLST and characteristic aspects of the TI-LLST are briefly reviewed, in which the main contents are limited in our own achievements, although other groups have also observed similar phenomena using different methods. In the sense of phenomenology, TI-LLST reported here is quite different from other recognized liquid transitions, i.e., there are only a few convincing cases of liquid P, Si, C, H2O, Al2O3-Y2O3, etc. in which the transition occurs, either induced by pressure or at a supercooled state and near liquidus.

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Section: The Effects Of Ti-llst On Solidification Behaviors and Strucmentioning

confidence: 99%

Temperature-Induced Liquid-Liquid Transition in Metallic Melts: A Brief Review on the New Physical Phenomenon

2015

Metals

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“…Some researchers pointed out that the consideration of the phase transformation kinetics is necessary to simulate the cooling curves in solidifying alloys. [19][20][21][22][23] In the present study, the temperature-enthalpy curve was modified based on the phase transformation kinetics.…”

Section: Sus304 Stainless Steelmentioning

confidence: 99%

Heat Transfer Analysis for Solidifying Ferrous Multi-component Alloys Using Computational Thermodynamics

Ohsasa¹,

Shirosawa²

2009

ISIJ Int.

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Temperature-enthalpy curves of ferrous multi-component commercial alloys of S45C steel, SUS304 stainless steel and FC200 cast iron were calculated based on the thermodynamic calculation using the ThermoCalc for both an equilibrium state and non-equilibrium state with no diffusion in solid. The heat transfer simulations during the solidification of the alloys based on the enthalpy method were carried out using the calculated temperature-enthalpy curves. Thermal analysis experiment of the alloys under a furnace cooling condition was carried out and measured cooling curves were compared with simulated ones. The simulated cooling curves of S45C carbon steel and SUS304 stainless steel obtained with the non-equilibrium condition showed similar shapes to the experimentally measured ones. Phase transformation kinetics during the eutectic solidification of FC200 cast iron was taken into account for calculating the temperature-enthalpy curve of FC200 cast iron and simulated cooling curve showed similar shape to measured cooling curve.

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“…CA-CCA techniques are most often used to investigate casting alloys; Stefanescu et al [11][12][13][14][15][16][17][18] used a CA-CCA technique in measuring the latent heat of pure aluminum and pure copper to establish the validity of this method. Prior to this study, this technique had not been used to investigate solder alloys.…”

Section: -7)mentioning

confidence: 99%

“…One technique was developed by Argyropoulos 19) and the other (the method used in this study) by Stefanescu. [11][12][13][14][15][16][17][18] The principles and procedures of Stefanescu's method are discussed here. The assumptions of CA-CCA are: (1) Cooling behavior of the molten metal in a small crucible can be considered to be a lumped system; the Biot number (Bi ¼ hV=Ak) is smaller than 0.1.…”

Section: Principle and Procedures Of Ca-ccamentioning

confidence: 99%

Pasty Ranges and Latent Heat Release Modes for Sn-9Zn-<i>x</i>Ag Lead-free Solder Alloys

Tsai

Hwang

2004

Mater. Trans.

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The pasty ranges and latent heat release modes of Sn-9Zn-xAg alloys, where x varies between 0.5 and 3.5, are examined in this study. The effects of alloy composition and cooling rate on the pasty range and latent heat release modes are also investigated. A Computer Aided-Cooling Curve Analysis (CA-CCA) technique is used to determine the pasty ranges and latent heat release modes for the alloys. To comply with the requirements of CA-CCA, the heat transfer conditions of the experimental setup must closely resemble of a lumped system, in which the alloy is cooled in a uniform fashion. To confirm this, two thermocouples are inserted into the crucible where the alloy is melted and subsequently resolidified. The crucible is used with and without a covering of insulating material to obtain different cooling rates. The temperature readings show that the heat transfer conditions in the experimental setup indeed meet the requirements of a lumped system. The solid fraction versus temperature relationship ( f s -T) for the various alloy compositions and cooling rates are obtained from the temperature data through CA-CCA. The experimental results show that as the silver content of the Sn-9Zn-xAg alloy increases, the liquidus temperature rises and the pasty range broadens. The pasty range is approximately 2 C for 0.5Ag, 9 C for 1.5Ag, 14 C for 2.5Ag, and 18 C for 3.5Ag. As long as the silver content is below 0.5 mass%, silver has little effect on the microstructure, which is basically the eutectic Sn-9Zn and the f s -T relationship is nearly a vertical line. However, as the silver content exceeds 1.5 mass%, the formation of Ag-Zn intermetallic compounds becomes obvious. This causes the alloy composition to deviate from eutectic and to lean towards the tin side of the Sn-Zn phase diagram. This in turn causes the proportion of the primary tin phase to increase and that of the zinc-tin eutectic phase to decrease. This is reflected on the plot of the f s -T relationship by two distinct vertical regions. One corresponds to the primary tin phase and the other to the eutectic phase. As the silver content further increases, the effects of intermetallic compound formation become even more obvious. As an alternative to CA-CCA, Huang's model can be used to obtain a quantitative f s -T function. As the silver content increases, the primary solid fraction for Huang's model increases. As the cooling rate increases, the primary solid fraction and the nonlinearity factors n e and n p decrease.

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Heat transfer-solidification kinetics modeling of solidification of castings

Cited by 121 publications

References 5 publications

Temperature-Induced Liquid-Liquid Transition in Metallic Melts: A Brief Review on the New Physical Phenomenon

Temperature-Induced Liquid-Liquid Transition in Metallic Melts: A Brief Review on the New Physical Phenomenon

Heat Transfer Analysis for Solidifying Ferrous Multi-component Alloys Using Computational Thermodynamics

Pasty Ranges and Latent Heat Release Modes for Sn-9Zn-<i>x</i>Ag Lead-free Solder Alloys

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