Elastic-plastic transition during nanoindentation in bulk GaN crystal

Masaki Fujikane*, Michał Leszczyński, Shijo Nagao, Tadachika Nakayama, Shinsuke Yamanaka, Koichi Niihara, Roman Nowak

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    42 Citations (Scopus)

    Abstract

    Mechanical properties of a defect-free bulk GaN single crystal has been studied by nanoindentation in the C (0001) surface. Our experiments provide consistent evaluations of Young's modulus (E = 320 GPa) measured with both Berkovich and spherical indenters. Additionally, Berkovich hardness (H = 17 GPa) and true hardness (Ht = 25 GPa) were determined. Pop-in events are confirmed to indicate the elastic-plastic transition of the material, and give also consistent yield (maximum) shear stress, τmax = 19 GPa, for both the indenters. To achieve these precise analyses, the effective curvature of the indenter was determined by the Hertz analysis of the contact between the indenter and a diamond crystal, in addition to the Oliver-Pharr method with a standard fused quartz.

    Original languageEnglish
    Pages (from-to)405-411
    Number of pages7
    JournalJournal of Alloys and Compounds
    Volume450
    Issue number1-2
    DOIs
    Publication statusPublished - 14 Feb 2008
    MoE publication typeA1 Journal article-refereed

    Keywords

    • Anisotropy
    • Elasticity
    • Mechanical properties
    • Nitride materials
    • Strain

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