Microscopic micro fibril orientation

In order to supplement micro-mechanical investigations and advance knowledge of the fracture process, micro-mechanical measurements in the deformation zone are required to determine local stresses and strains. In TPs, craze zones can develop that are important microscopic features around a crack tip governing strength behavior. For certain plastics fracture is preceded by the formation of a craze zone that is a wedge shaped region spanned by oriented micro-fibrils. Methods of craze zone measurements include optical emission spectroscopy, diffraction... 

Microstructure of crazes in thin films by transmission electron microscope. In thin PS films e (craze initiation) =1% Fibrils of 25-50 nm are a common feature of the microstructure of crazes in cast and bulky films. Major fibrils diameter = 20-30 nm. Minor fibrils connecting major fibrils have a diameter >10 nm and they tend to orient normally to major fibrils. At large total deformation at low e, there is a gradual transition from coarse to fine micro structure of crazes. Beahan, Bevis Hull (1151 PS... 

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