STP889

    Dislocation Aspects of Plastic Flow and Cracking at Indentations in Magnesium Oxide and Cyclotrimethylenetrinitramine Explosive Crystals

    Published: Jan 1985


      Format Pages Price  
    PDF Version (388K) 18 $25   ADD TO CART
    Complete Source PDF (4.9M) 18 $55   ADD TO CART


    Abstract

    Unique information about the hardness properties of crystalline materials can be obtained from studying the dislocation mechanisms involved in microindentation testing. The dislocation description provides information in addition to the knowledge of indentation processes gained from earlier continuum mechanics analyses and from models of the orientation dependence of hardness based on the geometrical arrangement of slip systems. For example, (1) mapping of the residual dislocation distributions within microindentation plastic zones can be used to characterize the deformation field and (2) specification of the dislocation interactions that occur among the crystal deformation systems is useful in evaluating the extent to which the hardness is affected by work hardening and cracking mechanisms. An interesting application of this information is to microindentation hardness testing of explosive crystals.

    Keywords:

    microindentation hardness, dislocations, pileups, cracking, scanning electron microscopy, X-ray topography, chemical etch pitting, magnesium oxide, cyclotrimethylenetrinitramine (RDX), energy dissipation, hot spots, microindentation hardness testing


    Author Information:

    Armstrong, RW
    Professor, University of Maryland, College Park, MD

    Elban, WL
    Materials research engineerassociate professor, Naval Surface Weapons CenterLoyola College, Silver SpringBaltimore, MDMD


    Paper ID: STP32954S

    Committee/Subcommittee: E04.05

    DOI: 10.1520/STP32954S


    CrossRef ASTM International is a member of CrossRef.