ISSN:
1573-9325
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Conclusions 1. The possibility of describing the kinetics of the development of the plastic zone using a semimicroscopic method that employs phenomenological equation (1) for the rate of local plastic strain and the distribution of dislocation charges Δρ (4), which determine the magnitude of the local stress, is indicated. 2. A pronounced separation of dislocation charges in the plastic zone, which can be interpreted as the outset of plastic rotations in the zone, is detected. 3. For selected parameter values corresponding to real single iron crystals, the deformation in the plastic zone is determined primarily by long-range hardening (by variation in σl as a result of the appearance of Δρ), and the contribution made by local hardening is only several percent. 4. Even at the level of fractions of a percent, deformation in the plastic zone results in the appearance of a new region of local overstress ahead of the crack tip — a region of instabilities. In this region, the deformations have a sign opposite to that of the deformations in the plastic zone. Moreover, large local-stress gradients, which contribute to the development of rotation instability develop here. This effect is apparently decisive for the initiation of a zone of instabilities ahead of the crack tip, and, consequently, for conditions favorable to macrocrack caving.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01523149
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