Finite element simulation of plane strain plastic-elastic indentation on single-crystal silicon

Meso-plasticity FEM technique was applied to simulate the dislocation gener ation and propagation during indentation of a single-crystal silicon. Dislo cations were generated and concentrated under the indenter and propagated i nto the interior of the workmaterial as the indentation progresses. Similar ly, the hydrostatic stress and the principal stress were concentrated direc tly underneath the indenter. The magnitudes of these stresses are found to increase with increase in the depth of indentation. It is proposed that pre -existing microcracks are not necessary for the defect generation in the wo rkmaterial. Instead, a concentration of dislocations generated by plastic d eformation under light loads and high hydrostatic pressures can play a simi lar role. The role of hydrostatic pressure in suppressing fracture was inve stigated. Based on these studies, it appears feasible to generate crack-fre e, smooth surfaces below a critical load or cut depth in ultraprecision mac hining of silicon. (C) 2000 Elsevier Science Ltd. All rights reserved.