Nanoindentation. Simulation of defect nucleation in a crystal.
Nanoindentation is the penetration of a surface to nanometre depths using an indenting device. It can be simulated using the Bragg bubble-raft model, in which a close-packed array of soap bubbles corresponds to the equilibrium positions of atoms in a crystalline solid. Here we show that homogeneous defect nucleation occurs within a crystal when its surface roughness is comparable to the radius of the indenter tip, and that the depth of the nucleation site below the surface is proportional to the half-width of the contact. Our results may explain the unusually high local stress required for defect nucleation in nano-indented face-centred cubic crystals.
Gouldstone
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Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Van Vliet
K J
KJ
Suresh
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