Crack Morphology in Relatively Brittle Crystals
From the viewpoint that cracks are atomically sharp, general outlines are given for some of the types of theories which should be developed for such cracks. The existence of atomic cleavage in a large class of materials is argued on the basis of the stability of a crack under spontaneous dislocation formation. A qualitative description of lattice trapping of a cleavage crack is given which correlates the effect to the atomic force laws. The determining factor for the observation of lattice trapping is the width of the cohesive region of the crack “core.” Finally, a qualitative model of slow crack growth due to environmental effects is developed in terms of atomic dissolution at the crack tip.
KeywordsStress Intensity Factor Slow Crack Growth Cleavage Crack Thermodynamic Equilibrium State Kink Site
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