Fracture environmental

Thompson, A.W. and Bernstein, I.M., The role of metallurgical variables in hydrogen-assisted environmental fracture, in Advances in Corrosion Science and Technology, Vol. 7, Fontana, M.G. and Staehle, R.W., Eds., Plenum Press, New York, 1980, pp. 53-175. 

The influence of solvents has been touched on in Sect. 2.3.2. In fact, the influence of environment on crazing and fracture properties of polymers is of major importance in the practical uses of these materials. There are many ways for the environment to induce fracture by means of stress cracking, stress crazing, chain scission, chain crosslinking, etc. Therefore, environmental fracture has been widely studied, specially from the experimental point of view. Reference is a review of environmental cracking of polymers. Most work on environmental crazing has been done in liquid environments - (solvents and non solvents of the material), or high pressure gas environment, near condensation pressure (liquid nitro-... 

Universal models of environmental fracture rarely survive for long, and SCC specialists such as Parkins [27,171] have devoted much effort to promoting a spectrum of mechanisms from mainly chemical (intergranular slip-dissolution) to mainly mechanical (hydrogen-induced SCC of high-strength steel). Nevertheless,... 

A. W. Thompson and 1. M. Bernstein, The role of metallurgical variables in hydrogen assisted environmental fracture, Rockwell Science Center Report SCPP-75-63,1975. J. P. Hirth, A/eto//. Trans. IIA 861-890 (1980). 

All the above modes of fracture are affected by the environment around the crack tip. This behaviour is typified by the phenomenon of stress-corrosion cracking where a crack, which is subjected to a subcritical stress concentration, will grow in a corrosive environment when /f, the critical stress concentration for stress-corrosion cracking). Therefore, to predict accurately the occurrence of cracking and crack growth rate, not only the materials properties are required but also information on the immediate environmental conditions. 

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