Discrete dislocation plasticity and crack tip fields in single crystals
نویسندگان
چکیده
منابع مشابه
Atomistic study of crack-tip cleavage to dislocation emission transition in silicon single crystals.
At low temperatures silicon is a brittle material that shatters catastrophically, whereas at elevated temperatures, the behavior of silicon changes drastically over a narrow temperature range and suddenly becomes ductile. This brittle-to-ductile transition has been observed in experimental studies, yet its fundamental mechanisms remain unknown. Here we report an atomistic-level study of a funda...
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Crack tip stress and deformation fields are analyzed for tensile-loaded ideally plastic crystals. The specific cases of (0 1 O) cracks growing in the [1 0 1] direction, and (1 0 1) cracks in the [0, 1, O] direction, are considered for both fcc and bcc crystals which flow according to the critical resolved shear stress criterion. Stationary and quasistatically growing crack fields are considered...
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We present results of molecular dynamic simulations aimed at examining crack tip dislocation emission in fcc solids. The results are analyzed in terms of recent continuum formulations of this problem. In mode II, Au, Pd, and Pt displayed a new unanticipated mechanism of crack tip dislocation emission involving the creation of a pair of Shockley partials on a slip plane one plane below the crack...
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Crack tip dislocations in silicon single crystals were observed by combining high-voltage electron microscopy and electron tomography. Cracks were introduced by an indentation method and dislocations were introduced around the crack tip by keeping the indented sample at high temperatures for several hours. The number of dislocations emitted from the crack tip was controlled by changing the hold...
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Recent ideas on the mechanisms controlling the initial stages of plastic flow at cracks in intrinsically brittle materials, at the ductile-brittle transition, are reviewed. New experiments on precracked specimens of Si are reported, which confirm earlier work that the ductile-brittle transition is controlled by dislocation velocity. A model has been developed in which at the ductile-brittle tra...
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ژورنال
عنوان ژورنال: Journal of the Mechanics and Physics of Solids
سال: 2001
ISSN: 0022-5096
DOI: 10.1016/s0022-5096(01)00040-0