Craze formation and cryogenic toughness

Crazing is the predominant plastic deformation mechanism in thermoplastics preceeding brittle fracture. The energies needed to form and to stretch crazes up to their break also mainly determine the fracture energy. Using the fracture mechanics approach together with the Dugdale type of plastic zone the single craze at a crack tip can be well characterized as may be seen from experimental investigations using the microscopic optical interference technique. At low temperatures the good deformation behaviour of PC is associated with the crazing mechanism