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Title: Brittle to ductile transition during compression of glassy nanoparticles studied in molecular dynamics simulations
Understanding how nanoparticles deform under compression is not only of scientific importance, but also has practical significance in various applications such as tribology, nanoparticle-based probes, and dry grinding of raw materials. In this study, we conducted compression tests on model brittle glassy nanoparticles using molecular dynamics simulations. We found that during the early stages of plastic deformation, shear bands formed in a similar pattern regardless of nanoparticle size. However, as the deformation continued, dominant cracks emerged in large nanoparticles while being suppressed in smaller ones. This size-dependent brittle to ductile transition can be explained by a simple model based on Griffith's theory. We also investigated the effect of surface stress state on fracture using thermally tempered nanoparticles. We observed that the presence of compressive surface stress strengthened the nanoparticle by suppressing crack formation, even when a pre-notch was present. On the other hand, tensile surface stress had the opposite effect. Interestingly, nanoparticles with both tensile and compressive surface stress promoted shear deformation, which could potentially compromise the mechanical performance of tempered glass despite delayed crack formation.  more » « less
Award ID(s):
1936368
NSF-PAR ID:
10492394
Author(s) / Creator(s):
; ;
Publisher / Repository:
AIP Publishing
Date Published:
Journal Name:
Journal of Applied Physics
ISSN:
0021-8979
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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