Energetics of residual dislocations associated with slip-twin and slip- GBs interactions
MD Sangid and T Ezaz and H Sehitoglu, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 542, 21-30 (2012).
During direct slip transmission of a dislocation through a twin or grain boundary, typically a residual dislocation remains in the boundary plane. Through atomistic simulations, we show systematic cases of slip transmission through various types of < 1 1 0 > tilts and < 1 1 1 > twists grain boundaries (GBs). Additionally, one specific type of GB, the coherent twin boundary (CTB), is viewed to investigate the effects of orientation and dislocation type on the slip transmission process. In every case, we measure the residual Burgers vector within the boundary and energy barrier for slip to transmit through the CTB or GB. There exists a direct correlation between the magnitude of the residual Burgers vector and the energy barrier for slip transmission. Hence, in cases of easy slip transmission (i.e. low energy barrier), a small residual dislocation is left in the GB; meanwhile in cases where it is difficult for slip to transmit past the CTB or GB (i.e. high energy barrier), a large residual Burgers vector remains within the boundary. (C) 2012 Elsevier B.V. All rights reserved.
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