High resolution transmission electron microscopy study in VC-doped WC-Co compound

T. Yamamoto, Y. Ikuhara, T. Sakuma

    Research output: Contribution to journalArticlepeer-review

    93 Citations (Scopus)

    Abstract

    Microstructure evolution in VC-doped WC-Co was investigated using high-resolution transmission electron microscopy (HRTEM) associated with X-ray energy dispersive spectroscopy (EDS) with a special interest in WC/Co and WC/WC boundaries. It was found that the morphology of carbide grains changed largely by the addition of VC. The WC/Co interfaces tend to form facetting with fine multi-steps of (0001) and {1010}habits by VC-doping. In addition, the facetting morphology of WC/Co interfaces was confirmed to be already formed in solid state from an examination with a quenched compound from 1200°C, which is below the eutectic temperature of 1320°C between WC and Co system. EDS analysis with the sub-nano scale probe revealed that the doped V was strongly concentrated to the two habits. However, the amount of concentrated V was different among them, i.e. more at (0001) habit than at {1010} habits. V is considered to be concentrate at the boundary during grain growth to accompany the migration of the two habits because most of the doped V solves into the Co-phase and not into WC grains. Thus it can be supposed that the retardation of the grain growth of WC grains is due to the concentration of V at the migration front of the two habits. Meanwhile, WC/WC boundaries were found to be directly in contact each other and free from the second phase such as the amorphous phase whereas the segregation of Co and also V could be detected by EDS analysis. This fact suggests that the grain boundary migration between the adjacent WC grains may be mainly controlled by the solid-solid diffusion.

    Original languageEnglish
    Pages (from-to)97-104
    Number of pages8
    JournalScience and Technology of Advanced Materials
    Volume1
    Issue number2
    DOIs
    Publication statusPublished - 2000 Jul

    Keywords

    • Boundaries
    • EDS
    • Grain growth
    • HRTEM
    • Microstructure
    • WC-CO

    ASJC Scopus subject areas

    • Materials Science(all)

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