Micromechanical and Macroscopic Modelling (MMM)
Crack tip dislocations and its shielding effect
M. Tanaka, Y. Hoshino, A. Hartmaier, K. Higashida.
Materials Science Forum, 561-565, 1833-1836, (2008)
Two dimensional simulations of discrete dislocation dynamics were carried out to clarify a shielding effect due to dislocations at a crack tip. The configuration of dislocations around the crack tip was calculated under the conditions of mode I tensile load at high temperatures. The stress field around the crack tip due to dislocations was found to be compressive, accommodating mode I stress intensity at the crack tip. In order to experimentally confirm the stress accommodation, infrared photoelastic observation was also performed in a specimen pre-deformed at high temperatures. The experimental result is in good agreement with a simulated infrared photoelastic image derived from the stress field calculated.
Keyword(s): silicon, stress accommodation, dislocation dynamics, infrared photoelasticity