Image icon  Crazing near a fracture surface in polycarbonate

Use this resource: Use this resource icon
Link to this page:
View at:            
Resource type: Image
Description: The fracture surface shows fibrils of oriented polymer which are the remnants of crazes. Crazes are both a precursor to cracking and a toughening mechanism in stressed polymers. They only form when a certain critical tensile stress has been attained and form perpendicular to the largest tensile principal stress. They are very fine crack-like projections from the fracture surface but are bridged by even finer material, giving approximately 50% voids. It is these fibrils which interfere with light in an otherwise transparent polymer to make the crazing visible as a whitening of the strained material. The surface ridging, parallel to the principal stress, is a consequence of strain-induced crystallisation during the cold drawing of the polycarbonate.
Keywords: craze • fibril • fracture • polycarbonate (PC) • polymer
Categories: Science approaches > Deformation & failure > Fracture
Science approaches > Microstructure
Materials > Polymers & elastomers > Plastics > Thermoplastics > Polycarbonate (PC)
Testing, analysis & experimentation > Metallography
Scale > Micro
Created by: DoITPoMS, University of Cambridge
J A Curran, Department of Materials Science and Metallurgy, University of Cambridge
Published by: DoITPoMS, University of Cambridge
License: This resource is released under the Creative Commons Attribution Non-Commercial Share Alike license (2.0 UK: England & Wales).
Creative Commons Attribution Non-Commercial Share Alike logo
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).
  • noncommercial – You may not use this work for commercial purposes.
  • share alike – If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.
View the full legal code here.
Date created: 03 October 2002
Date added: 21 August 2009
Resource ID: 1624