Discrete Dislocation Dynamics Simulation of Interfacial Dislocation Network in Gamma/Gamma-Prime Microstructure of Ni-based Superalloys
K. Yashiro; Y. Nakashima and Y. Tomita

Source CMES: Computer Modeling in Engineering & Sciences, Vol. 11, No. 2, pp. 73-80, 2006
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Keywords Discrete Dislocation Dynamics, Anti-Phase Boundary, Ni-Based Superalloys, Interfacial Dislocation Network
Abstract A simple back force model is proposed for a dislocation cutting into$\gamma \tmspace +\thinmuskip {.1667em}\tmspace +\thinmuskip {.1667em}'$ precipitate, taking the work for making and recovering an anti-phase boundary (APB) into account. The first dislocation, or a leading partial of a superdislocation, is acted upon by a back force whose magnitude is equal to the APB energy. The second dislocation, or a trailing partial of a superdislocation, is attracted by the APB with a force of the same magnitude. The model is encoded in the 3D discrete dislocation dynamics (DDD) code and applied to the cutting behavior of dislocations at a$\gamma / \gamma \tmspace +\thinmuskip {.1667em}\tmspace +\thinmuskip {.1667em}'$ interface covered by an interfacial dislocation network. Dislocations are generated from Frank-Read sources and approach the interface. The first dislocation piles up at the interface not by the stress field of the network but by the back force against making an APB. The second dislocation, however, stands off from the interface by the stress field of the first dislocation and the dislocation network. The finer mesh of the network, the further the second dislocation piles up. These two dislocations cut into the precipitate forming a superdislocation under the force from follow-on dislocations. It is also clarified that the penetration takes place from the interspace of the network.
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