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):

Report Date:

1993-01-01

Pagination or Media Count:

294.0

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.

Subject Categories:

  • Polymer Chemistry
  • Laminates and Composite Materials
  • Crystallography
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE