Dynamic compressive failure of AlON under controlled planar confinement

Bhasker Paliwal, Kaliat T. Ramesh, James W. McCauley, Mingwei Chen

    Research output: Contribution to journalArticle

    47 Citations (Scopus)

    Abstract

    An experimental technique is developed to impose a planar lateral confinement in a prismatic specimen (with a rectangular cross section); the setup enabled a controlled and homogeneous stress state with high lateral compressive stresses. A transparent polycrystalline aluminum oxynitride (AlON) specimen was used for the study. The statically precompressed specimen was then subjected to axial dynamic compressive loading using a modified compression Kolsky bar setup. Experimental design was performed using 3D computational modeling. Initial exploratory experiments were conducted on AlON at an average planar confinement of 400-410 MPa; the results suggested a higher compressive strength and a nonlinear stress evolution in AlON due to the confinement. A high-speed camera was used to observe the damage evolution in the specimen during the course of loading. The photographs and stress evolution are suggestive of an additional inelastic deformation mechanism, whose evolution is slower than the typical brittle-cracking type of damage apparent in the unconfined case. The TEM and high-resolution electron microscope analysis indicated dislocation plasticity in some fragments; dislocations in the slip bands were characterized to be dissociated 〈110〉 dislocations on {111} planes. The width between two partial dislocations was about 15 nm, suggesting low stacking fault energy of AlON. Microscopic characterization also shows that the eventual fragmentation of AlON is by cleavage mainly along low-index {111} planes.

    Original languageEnglish
    Pages (from-to)3619-3629
    Number of pages11
    JournalJournal of the American Ceramic Society
    Volume91
    Issue number11
    DOIs
    Publication statusPublished - 2008 Nov 1

    ASJC Scopus subject areas

    • Ceramics and Composites
    • Materials Chemistry

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