A quantitative understanding on effects of finest nanograins on nanovoid growth in nanocrystalline materials
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For evaluating the effects of finest nanograins, whose grain size ranging from 2 to 4 nm, on nanovoid growth in nanocrystalline (NC) materials, we proposed a new theoretical model composed of finest nanograins evenly located at the triple junctions of conventional NC materials (grain size ranging from 10 to 100 nm). In the framework of the model, the mechanism of nanovoid growth is the dislocation emission. The blocking effect of finest nanograin on the motion of dislocations emitted from the nanovoid surface was taken into consideration. The critical condition required for dislocations emitted from the nanovoid surface and the influences of the finest nanograin on the nanovoid growth were calculated separately. The quantitatively analyzed results showed that finest nanograins could significantly suppress the growth of nanovoids compared with the triple junctions without finest nanograins. Therefore, the fracture toughness of the NC materials could be enhanced by finest nanograins.
KeywordsNanovoid growth Finest nanograin Dislocation Triple junction Theory Modeling and simulations
This work was supported by Key Project of Chinese Ministry of Education (211061), National Natural Science Foundation of China (10502025, 10872087, 11272143), Program for Chinese New Century Excellent Talents in University (NCET-12-0712), and PhD Programs Foundation of Ministry of Education of China (20133221110008).
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Conflict of Interest
The authors declared that they have no conflicts of interest to this work.