Microstructural characterization of Co-based coating deposited by low power pulse laser cladding

A. Farnia, F. Malek Ghaini*, V. Ocelik, J. Th. M. De Hosson

*Corresponding author for this work

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    Abstract

    A detailed microstructural study of Stellite 6 coating deposited on a low carbon ferritic steel substrate using preplaced powder method and low power Nd:YAG pulse laser is performed. The grain structure and solidification texture of the coating are investigated by orientation imaging microscopy (OIM) and scanning electron microscopy. In addition, the effect of consecutive pulses on the microstructure of the coating is examined. The orientation relationship (OR) at coating/substrate interface and the solid state phase transformation in heat-affected zone are studied as well as the Vickers microhardness profile measurement in order to support the microstructural observations. An important conclusion is reached that the shape of solidification front during pulsed laser cladding is similar to the shape of solidification front during continuous cladding with a doubled laser beam scanning speed. Further, OIM reveals the Greninger-Troiano OR between the face centered cubic coating and bcc substrate grains. It is concluded that at the moment of solidification epitaxial growth of the grains in the coating occur on the austenitic grains of the substrate and that an austenite-ferrite transformation occurs in the heat-affected zone upon subsequent cooling.

    Original languageEnglish
    Pages (from-to)2714-2723
    Number of pages10
    JournalJournal of Materials Science
    Volume48
    Issue number6
    DOIs
    Publication statusPublished - Mar-2013

    Keywords

    • WEAR-RESISTANCE
    • ALLOY
    • TI-6AL-4V
    • STEEL

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