Nanoindentation-Induced Collective Dislocation Behavior and Nanoplasticity |
| Journal |
Key Engineering Materials (Volumes 340 - 341) |
| Volume |
Engineering Plasticity and Its Applications |
| Edited by |
N. Ohno and T. Uehara |
| Pages |
39-48 |
| DOI |
10.4028/www.scientific.net/KEM.340-341.39 |
| Online since |
June, 2007 |
| Authors |
Yoji Shibutani,
Tomohito Tsuru
|
| Keywords |
Copper (Cu), Dislocation Emission, Displacement Burst, Nanoindentation, Nanoplasticity, Prismatic Dislocation Loop, Single Crystalline Aluminium |
| Abstract |
The present paper summarizes the crystallographic dependence of the displacement burst
behavior observed in nanoindentation using two single crystalline aluminum (Al) materials and
copper (Cu) with three kinds of surface indices, namely (001), (110) and (111). From the critical
indent load at the first burst, the critical resolved shear stresses (CRSSs) of the collective dislocation
nucleation were estimated in reference to molecular dynamics (MD) simulations. These are almost
one-tenth of the shear modulus, which are close to the ideal values. We explain the nanoplastic
mechanics by a comprehensive energy balance model to describe the linear relation between the
indent load and the burst width of the first displacement burst and by the nucleation model consisting
of three-dimensional discrete dislocations to evaluate the number of dislocations nucleating. The
distance between the emitted dislocation loops of Al is found to be fairly large. Thus, Al is expected
to exhibit a less tangled network of dislocations just below the indentation than Cu, which has a lower
stacking fault energy. |
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