Accession Number : ADA261703


Title :   Defect Initiation/Growth and Energy Dissipation Induced by Deformation and Fracture


Descriptive Note : Annual technical rept. 15 Jun 91-14 Dec 92,


Corporate Author : WASHINGTON STATE UNIV PULLMAN DEPT OF PHYSICS


Personal Author(s) : Dickinson, J T


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a261703.pdf


Report Date : Jan 1993


Pagination or Media Count : 294


Abstract : Based on our capabilities to (1) detect and characterize particle release from surfaces on fast time scales, (2) to measure rapid electrical transients, and (3) to obtain high resolution topographical information utilizing scanning tunneling and atomic force microscopy, we present new results on the time sequence of events leading up to defect Initiation and growth which ultimately leads to fracture. We employ dynamic methods as well as post-fracture examination in polymers, ceramics, metals, and interfaces. We emphasize mechanisms, with interpretation and connections between these results and the creation and evolution of defects in materials under mechanical stress. In many cases, the information we are acquiring has important implications concerning dissipation of energy (e.g., plastic deformation, microcracking, crack branching, and crack deflection) which play critical roles in controlling the strength and toughness of materials.... Deformation, Crack propagation, Fracture, Particle emission, Fracto-emission interfacial failure, Crazing, Electrical transients, Microcracking, Surface charge, Fractography, Crystal defects, Scanning tunneling microscopy, Photoluminescence.


Descriptors :   *DEFORMATION , *ENERGY , *DISSIPATION , *CRYSTAL DEFECTS , *FRACTURE(MECHANICS) , SCANNING , PLASTIC DEFORMATION , STRESSES , TRANSIENTS , EMISSION , METALS , DEFLECTION , ELECTRON MICROSCOPY , TIME , SEQUENCES , STRENGTH(MECHANICS) , ELECTRICAL PROPERTIES , TOPOGRAPHY , HIGH RESOLUTION , TOUGHNESS , FAILURE , MICROCRACKING , CRAZING , STATIC ELECTRICITY , TUNNELING , PARTICLES , CRACK PROPAGATION , CERAMIC MATERIALS , SURFACES , FRACTOGRAPHY , RESOLUTION , PROPAGATION , DYNAMICS , INTERFACES , MATERIALS , POLYMERS , PHOTOLUMINESCENCE


Subject Categories : Polymer Chemistry
      Laminates and Composite Materials
      Crystallography
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE