Lamellarrod transition mechanism under high growth velocity condition

Wang, Lei; Wang, Nan; Lin, Ji; Wen-Jing, Yao

doi:10.7498/aps.62.216801

Acta Phys. Sin.

2013

DOI: 10.7498/aps.62.216801

|View full text |Cite

Lamellarrod transition mechanism under high growth velocity condition

Lei Wang¹,

Nan Wang²,

Ji Lin³

et al.

Abstract: At a low velocity, the lamellarrod eutectic transition can be controlled by the volume fraction of one eutectic phase only. The factors which affect this kind of transition at high growth velocities are not clear. Based on the competitive growth rule, the criterion for lamellarrod transition is obtained by combining the models of lamellar and rod eutectic growth under rapid solidification conditions. It is shown that for a certain volume fraction, if its value fluctuates around the critical point predicted by … Show more

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...

Citation Types

Supporting

Mentioning

Contrasting

Year Published

2014

2021

Publication Types

Select...

Article4

Relationship

Self Cite0

Independent4

Authors

Journals

Cited by 4 publications

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Rod eutectic growth in bulk undercooled melts

Zhang

Galenko

2021

Math Methods in App Sciences

View full text Add to dashboard Cite

This article proposes an analytical model to understand the rod growth of eutectic in the bulk undercooled melt. Based on the previous derivations of the lamellar eutectic growth models, relaxing the assumptions of small Péclet numbers, the model is derived by considering melt kinetic and thermal undercoolings. The intent of this model is to predict the transitions in eutectic pattern for conditions of the low and high growth velocities. In addition to investigation of the transition between lamellar and rod eutectic patterns, mathematical simplifications of solving Bessel function are presented as well, which is the most important priority to model calculation.

show abstract

Rod eutectic growth in bulk undercooled melts

Zhang

Galenko

2021

Math Methods in App Sciences

View full text Add to dashboard Cite

show abstract

Characteristic scale selection of lamellar spacings in binary eutectic solidification

Guo¹,

Xin²

2014

Acta Phys. Sin.

View full text Add to dashboard Cite

The lamellar spacing, which is formed by solidified melt of eutectic or near-eutectic composition, plays a very important role in determining the properties of final products. In this study, the lamellar spacing of eutectic growth in steady-state is predicted by the method which is established based on the classical Jackson-Hunt theory, and completed by considering the free energy change during eutectic solidification at small undercooling. The density difference between the solid phases is also considered when calculating the diffusion field in the liquid. It is found that a band of lamellar spacings would be generally selected for a given alloy under fixed growth conditions. In addition, the lamellar spacing can be morphologically stable below the minimum undercooling value, and this overstabilization is only dependent on the intrinsic characteristic properties of a given system at a fixed growth velocity. The analysis results are found to be in reasonable agreement with experimental data of Al-Al2Cu, Sn-Pb and CBr4-C2Cl6 systems available from the literature.

show abstract

Microstructural evolution of laser surface remelting remolten Ni-28 wt%Sn alloy under liquid nitrogen cooling

Cao¹,

Xin²,

Wang³

et al. 2015

Acta Phys. Sin.

View full text Add to dashboard Cite

The substrate of as-cast Ni-28 wt% Sn hypoeutectic alloy immersed in liquid nitrogen is rapidly remolten and solidified by laser surface remelting with a scanning velocity of 10 mm/s and the laser power of 1950 W. The microstructure of the substrate and its effect on the microstructure of the molten pool are investigated by scanning electron microscope carefully. It is found that the substrate of the Ni-28 wt%Sn ingot is composed of coarse primary α-Ni dendrites and the interdendritic (α-Ni+Ni3Sn) eutectic. The growth orientations of α-Ni dendrites and the interdendritic eutectic are distributed nearly randomly in the as-cast substrate. There are three kinds of microstructure characterstic zones from the top to the bottom of melted pool. The growth directions of α-Ni dendrites with the primary dendritic spacings ranging from 4.19 to 6.91 μm are approximately parallel to the laser scanning direction at the top of the molten pool due to the fact that the temperature gradient at the interface between the molten pool and substrate tends to be parallel to the laser scanning direction. In the middle of the molten pool, the epitaxial α-Ni columnar dendrites are found to be inclined to grow in the direction vertical to the bottom of the molten pool due to the fact that the temperature gradients in most zones of the molten pool are perpendicular to the bottom of the molten pool. The formation of new primary dendrites by the growth of the tertiary arm results in the decrease of primary dendritic spacing in comparison with that at the bottom of the molten pool. There are a small quantity of residual α-Ni primary phase and a large amount of (α-Ni+Ni3Sn) eutectic at the bottom of the molten pool. The microstructure of laser remolten zone is greatly influenced by the substrate microstructure, and the growth direction of the α-Ni dendrite in the molten pool is also affected remarkably by both the heat flux and the preferred crystal orientations for dendritic growth. Compared with the mixed lamella, rod and divorced (α-Ni+Ni3Sn) eutectic microstructures in the substrate, the eutectic structure in the molten pool is completely composed of the refined lamellar eutectic, which grows epitaxially in the direction perpendicular to the interface between the molten pool and the substrate at the bottom of molten pool. The eutectic lamellar spacing increases from the top (0.23 μm± 0.01 μm) to the bottom (0.42 μm± 0.02 μm) of the molten pool due to the interface growth velocity decreasing from the top to the bottom. The Kurz-Giovanola-Trivedi model for rapid dendritic growth and the Trivedi-Magnin-Kurz model for eutectic growth are used to estimate the growth undercooling of the microstructure in the molten pool respectively. It is found that the growth undercooling of dendrites and the eutectic in the molten pool should be between 50.4 K and 112.5 K, which is much larger than the critical undercooling for anomalous eutectic growth found in the high undercooled solidification in the previous researches. This phenomenon means that the critical undercooling for anomalous eutectic growth reported in the previous literature may be not the sufficient condition for generating the anomalous eutectic.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Lamellarrod transition mechanism under high growth velocity condition

Cited by 4 publications

References 11 publications

Rod eutectic growth in bulk undercooled melts

Rod eutectic growth in bulk undercooled melts

Characteristic scale selection of lamellar spacings in binary eutectic solidification

Microstructural evolution of laser surface remelting remolten Ni-28 wt%Sn alloy under liquid nitrogen cooling

Contact Info

Product

Resources

About