scholarly journals Cellular Automaton Simulation of the Growth of Anomalous Eutectic during Laser Remelting Process

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1844 ◽  
Author(s):  
Lei Wei ◽  
Yongqing Cao ◽  
Xin Lin ◽  
Weidong Huang
Keyword(s):  
Cellular Automaton ◽  
Cooling Rate ◽  
Eutectic Growth ◽  
The Other ◽  
Competitive Growth ◽  
Laser Remelting ◽  
Lamellar Eutectic ◽  
Melt Pool ◽  
Ca Model ◽  
Anomalous Eutectic

Anomalous eutectic morphologies were observed during laser remelting of a Ni-Sn powder bed, where it was sandwiched between a lamellar eutectic at the bottom of melt pool. That is, the anomalous eutectic growth mechanism can be divided into two processes: one is the lamellar to anomalous transition (LAT); the other is the anomalous to lamellar transition (ALT). The thermal distribution at the bottom of melt pool is simulated by the finite difference method. It is found that the cooling rate at the bottom of melt pool is a linear function of time. A cellular automaton (CA) model is developed to simulate the anomalous growth. Simulation results show that the mechanism of the LAT is that one phase overgrows the other followed by subsequent nucleating of the other phase. The mechanism of the ALT is the competitive growth between the anomalous and lamellar eutectic; as the cooling rate increased, the lamellar eutectic is more competitive.

A cellular automaton simulation of W–Ni alloy solidification in laser solid forming process

2017 ◽  
Vol 02 (04) ◽  
pp. 1750016
Author(s):  
Haiou Yang ◽  
Lei Wei ◽  
Xin Lin
Keyword(s):  
Cellular Automaton ◽  
Laser Remelting ◽  
Dimensional Model ◽  
Forming Process ◽  
Microstructure Simulation ◽  
Melt Pool ◽  
Laser Solid Forming ◽  
Ni Alloy ◽  
Ca Model ◽  
Metallurgy Process

An alloy cellular automaton (CA) model is developed for the microstructure simulation in directional solidification and laser solid forming (LSF) process. The CA model's capture rule was modified by a limited neighbor solid fraction (LNSF) method. A multiscale two-dimensional model is presented for simulating laser remelting process, which is the same as LSF without the addition of metallic powders into melt pool. The metallurgy process in melt pool was simulated, including temperature distribution, pool shape and solidification of microstructure. The microstructure evolution of tungsten–nickel alloy (W–Ni) during LSF is also simulated by present CA model.

Regular eutectic and anomalous eutectic growth behavior in laser remelting of Ni-30wt%Sn alloys

2017 ◽  
Vol 126 ◽  
pp. 210-220 ◽  
Author(s):  
Xin Lin ◽  
Yong-Qing Cao ◽  
Zhi-Tai Wang ◽  
Jun Cao ◽  
Li-Lin Wang ◽  
...  
Keyword(s):  
Eutectic Growth ◽  
Growth Behavior ◽  
Laser Remelting ◽  
Anomalous Eutectic

Quantitative cellular automaton model and simulations of dendritic and anomalous eutectic growth

2019 ◽  
Vol 156 ◽  
pp. 157-166 ◽  
Author(s):  
Lei Wei ◽  
Yongqing Cao ◽  
Xin Lin ◽  
Meng Wang ◽  
Weidong Huang
Keyword(s):  
Cellular Automaton ◽  
Eutectic Growth ◽  
Cellular Automaton Model ◽  
Anomalous Eutectic

Local solidification thermal parameters affecting the eutectic extent in Sn-Cu and Sn-Bi solder alloys

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rafael Kakitani ◽  
Cassio Augusto Pinto da Silva ◽  
Bismarck Silva ◽  
Amauri Garcia ◽  
Noé Cheung ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Thermal Gradient ◽  
Experimental Spectrum ◽  
Eutectic Growth ◽  
Solidification Velocity ◽  
Solder Alloys ◽  
Content Type ◽  
Growth Zones ◽  
Coupled Growth

Purpose Overall, selection maps about the extent of the eutectic growth projects the solidification velocities leading to given microstructures. This is because of limitations of most of the set of results when obtained for single thermal gradients within the experimental spectrum. In these cases, associations only with the solidification velocity could give the false impression that reaching a given velocity would be enough to reproduce a result. However, that velocity must necessarily be accompanied by a specific thermal gradient during transient solidification. Therefore, the purpose of this paper is to not only project velocity but also include the gradients acting for each velocity. Design/methodology/approach Compilation of solidification velocity, v, thermal gradient, G, and cooling rate, Ṫ, data for Sn-Cu and Sn-Bi solder alloys of interest is presented. These data are placed in the form of coupled growth zones according to the correlated microstructures in the literature. In addition, results generated in this work for Sn-(0.5, 0.7, 2.0, 2.8)% Cu and Sn-(34, 52, 58)% Bi alloys solidified under non-stationary conditions are added. Findings When analyzing the cooling rate (Ṫ = G.v) and velocity separately, in or around the eutectic composition, a consensus cannot be reached on the resulting microstructure. The (v vs. G) + cooling rate diagrams allow comprehensive analyzes of the combined v and G effects on the subsequent microstructure of the Sn-Cu and Sn-Bi alloys. Originality/value The present paper is devoted to the establishment of (v vs. G) + cooling rate diagrams. These plots may allow comprehensive analyses of the combined v and G effects on the subsequent microstructure of the Sn-Cu and Sn-Bi alloys. This microstructure-processing mapping approach is promising to predict phase competition and resulting microstructures in soldering of Sn-Cu and Sn-Bi alloys. These two classes of alloys are of interest to the soldering industry, whereas manipulation of their microstructures is considered of utmost importance for the metallurgical quality of the product.

Effect of behavioral variables on cooling rate of man in cold water

1975 ◽  
Vol 38 (6) ◽  
pp. 1073-1077 ◽  
Author(s):  
J. S. Hayward ◽  
J. D. Eckerson ◽  
M. L. Collis
Keyword(s):  
Body Size ◽  
Cooling Rate ◽  
Rectal Temperature ◽  
Body Surface ◽  
Cold Water ◽  
The Other ◽  
Ocean Water ◽  
Protective Behaviors ◽  
Control Behavior ◽  
Behavioral Variables

Five different behaviors of man while in cold ocean water (9–10 degrees C) were assessed for their effect on rate of progress into hypothermia. With subjects wearing lifejackets, two thermally protective behaviors were studied which reduce exposure to the water of areas of body surface with high relative heat loss potential. One was huddling of three persons and the other a self-huddle behavior (HELP or Heat Escape Lessening Posture). These two behaviors resulted in significant reductions of rectal temperature cooling rate of 66 per cent and 69 per cent, respectively, of that of a control behavior. With no flotation available, two survival swimming behaviors (treading water and drownproofing) were shown to result in significant increases in cooling rate to 134 per cent and 182 per cent, respectively, of the control behavior. Potential swimming distance of subjects wearing a life-jacket was 0.85 miles in water near 12 degrees C before predicted incapacitation by hypothermia. It was concluded that behavioral variables can be of major importance in determining survival time in cold water through modulation of cooling rate associated with other variables such as fatness, body size, and clothing.

Dendritic Growth of Rapid-Solidified Eutectic High-Entropy Alloy

2021 ◽  
Vol 1035 ◽  
pp. 46-50
Author(s):  
Lei Gang Cao ◽  
Peng Yu Hou ◽  
Ahmed Nassar ◽  
Andrew M. Mullis
Keyword(s):  
Cooling Rate ◽  
Single Phase ◽  
Eutectic Growth ◽  
Sample Surface ◽  
Eutectic Structure ◽  
High Entropy Alloy ◽  
Drop Tube ◽  
Dendrite Morphology ◽  
High Entropy ◽  
Mould Casting

Mould casting and drop-tube techniques were used to solidify a AlCoCrFeNi2.1 eutectic high-entropy alloy under conditions of high cooling rate. The samples obtained from two different methods present the same phase constituent, FCC and B2 phases. During mould casting experiments the alloy almost solidified into the eutectic structure consisting of lamellar and anomalous morphology, with a tiny fraction of cellular and dendrite morphology being observed at certain sites of the sample surface due to the corresponding high cooling rate. Instead, during drop-tube experiments a typical, coarse dendrite structure of FCC single phase was formed across the entire 106-150 μm particle. The cellular structure can also be formed directly from the melt. The rest region solidified into the general eutectic morphology as was observed in the casting rods. The results clearly indicate the transition from coupled eutectic growth to single-phase dendrite growth with increasing departures from equilibrium for the multi-component AlCoCrFeNi2.1 eutectic high-entropy alloy.

Cooling rate studies of rocks from two basic dykes

1982 ◽  
Vol 46 (340) ◽  
pp. 387-394 ◽  
Author(s):  
G. M. Corrigan
Keyword(s):  
Crystal Growth ◽  
Cooling Rate ◽  
Incubation Period ◽  
The Other ◽  
Textural Features ◽  
Variable Rate ◽  
Constant Rate ◽  
Loop Technique ◽  
Basaltic Melts ◽  
Cooling Model

SynopsisNucleation and crystal growth of plagioclase have been studied in two basaltic melts by one atmosphere, constant-rate and variable-rate cooling experiments using the wire-loop technique (Donaldson et al., 1975). Constant-rate cooling studies indicate that the length of the incubation period prior to nucleation varies systematically with the degree of supercooling and with the cooling rate. Attempts to determine the rates at which the marginal parts of two dykes (from the Isle of Arran, SW Scotland) cooled, by the attempted reproduction of the natural textural features, in constant-rate cooling experiments suggest that for one of the dykes, plagioclase phenocrysts at the contact could have grown at a cooling rate of approximately 3°C/hour and the groundmass plagioclase laths at faster cooling rates in excess of 10°C/hour. For the other dyke the plagioclase laths in the rocks 0.5 cm from the dyke contact probably grew at rates slower than 2°C/hour. Attempts to validate experimentally the Jaeger (1957) cooling model for the two dykes suggest that the dykes cooled at much slower rates than the theory predicts.

scholarly journals Cellular Automaton Modeling of Phase Transformation of U-Nb Alloys during Solidification and Consequent Cooling Process

2019 ◽  
Vol 38 (2019) ◽  
pp. 567-575 ◽  
Author(s):  
Qingfu Tang ◽  
Dong Chen ◽  
Bin Su ◽  
Xiaopeng Zhang ◽  
Hongzhang Deng ◽  
...  
Keyword(s):  
Cellular Automaton ◽  
Microstructure Evolution ◽  
Optical Microscope ◽  
Phase Precipitation ◽  
Cooling Process ◽  
Dendrite Morphology ◽  
Ca Model ◽  
Measuring Experiment ◽  
Kinetics Of ◽  
Cast Microstructure

AbstractThe microstructure evolution of U-Nb alloys during solidification and consequent cooling process was simulated using a cellular automaton (CA) model. By using this model, ϒ phase precipitation and monotectoid decomposition were simulated, and dendrite morphology of ϒ phase, Nb microsegregation and kinetics of monotectoid decomposition were obtained. To validate the model, an ingot of U-5.5Nb (wt.%) was produced and temperature measuring experiment was carried out. As-cast microstructure at different position taken from the ingot was investigated by using optical microscope and SEM. The effect of cooling rate on ϒ phase precipitation and monotectoid decomposition of U-Nb alloys was also studied. The simulated results were compared with the experimental results and the capability of the model for quantitatively predicting the microstructure evolution of U-Nb alloys during solidification and consequent cooling process was assessed.

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