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

    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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