Effect of temperature on dislocation emission from crack tip for BCC metal Mo |
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Authors: | Tang Qiheng and Wang Tzuchiang |
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Institution: | (1) LNM, Institute of Mechanics, Chinese Academy of Sciences, 100080 Beijing, China |
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Abstract: | The effect of thermally activated energy on the dislocation emission from a crack tip in BCC metal Mo is simulated in this
paper. Based on the correlative reference model on which the flexible displacement boundary scheme is introduced naturally,
the simulation shows that as temperature increases the critical stress intensity factor for the first dislocation emission
will decrease and the total number of emitted dislocations increase for the same external load. The dislocation velocity and
extensive distance among partial dislocations are not sensitive to temperature. After a dislocation emission, two different
deformation states are observed, the stable and unstable deformation states. In the stable deformation state, the nucleated
dislocation will emit from the crack tip and piles up at a distance far away from the crack tip, after that the new dislocation
can not be nucleated unless the external loading increases. In the unstable deformation state, a number of dislocations can
be emitted from the crack tip continuously under the same external load.
The project is supported by the National Natural Science Foundation of China. |
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Keywords: | correlative reference model flexible displacement boundary molecular dynamics dislocation emission temperature |
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