Title

Interfacial instability and microstructural growth due to rapid solidification in laser processing

Authors

Authors

W. Guo;A. Kar

Comments

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Abbreviated Journal Title

Acta Mater.

Keywords

DIRECTIONAL SOLIDIFICATION; ALLOYS; MELT; Materials Science, Multidisciplinary; Metallurgy & Metallurgical; Engineering

Abstract

Inherent rapid solidification during laser processing, such as laser cladding or surface alloying, can produce finer and newer microstructures having stable and metastable phases. A mathematical model is provided to predict and control rapidly solidified microstructures by analyzing the instability of the solid-liquid interface. The diffusion of solute atoms in the melt is analyzed by considering the nonequilibrium partition coefficient at the solid-liquid interface. The energy balance at the solid-liquid interface is used to examine the motion of the interface. Applying a small perturbation to the interface, the instability of the interface under different solidification conditions is discussed from the solution of the perturbed heat and mass transfer problems. The results demonstrate the influence of the solidification rate and partition coefficient on the instability of the interface leading to the formation of different types of microstructures. It is therefore possible to predict the microstructures by relating them to the nature of the interfacial instability. The results of this model indicate good agreement with the results of other models, and experimental data for the Fe-Ni alloys. (C) 1998 Acta Metallurgica Inc.

Journal Title

Acta Materialia

Volume

46

Issue/Number

10

Publication Date

1-1-1998

Document Type

Article

Language

English

First Page

3485

Last Page

3490

WOS Identifier

WOS:000074646500014

ISSN

1359-6454

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