Stress-assisted grain boundary sliding and migration at finite temperature: A molecular dynamics study

2004 ◽  
Vol 70 (5) ◽  
Author(s):  
Motoyuki Shiga ◽  
Wataru Shinoda
Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5351
Author(s):  
Ahmed Tamer AlMotasem ◽  
Matthias Posselt ◽  
Tomas Polcar

In the present work, modified embedded atom potential and large-scale molecular dynamics’ simulations were used to explore the effect of grain boundary (GB) segregated foreign interstitials on the deformation behavior of nanocrystalline (nc) iron. As a case study, carbon and nitrogen (about 2.5 at.%) were added to (nc) iron. The tensile test results showed that, at the onset of plasticity, grain boundary sliding mediated was dominated, whereas both dislocations and twinning were prevailing deformation mechanisms at high strain. Adding C/N into GBs reduces the free excess volume and consequently increases resistance to GB sliding. In agreement with experiments, the flow stress increased due to the presence of carbon or nitrogen and carbon had the stronger impact. Additionally, the simulation results revealed that GB reduction and suppressing GBs’ dislocation were the primary cause for GB strengthening. Moreover, we also found that the stress required for both intragranular dislocation and twinning nucleation were strongly dependent on the solute type.


2020 ◽  
Vol 180 ◽  
pp. 97-102 ◽  
Author(s):  
Qizhen Li ◽  
Lihua Wang ◽  
Jiao Teng ◽  
Xiaolu Pang ◽  
Xiaodong Han ◽  
...  

2004 ◽  
Vol 467-470 ◽  
pp. 545-550 ◽  
Author(s):  
David J. Prior ◽  
Michel Bestmann ◽  
Angela Halfpenny ◽  
Elisabetta Mariani ◽  
Sandra Piazolo ◽  
...  

Misorientation analysis, using EBSD data sets, has enabled us to constrain better recrystallization mechanisms in rocks and minerals. Observed microstructures are not explicable in terms of recovery, boundary bulging and migration alone. We have to invoke either a nucleation process (physics unknown) or grain rotations that are not related to grain or boundary crystallography. Such rotations can occur by diffusion accommodated grain boundary sliding and this mechanism explains best the microstructure and texture of recrystallized grains in some rocks.


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