Dislocation Dynamics Simulations of Dislocation-Particle Bypass Mechanisms

Abstract:

Effect of precipitation strengthening on metal is generally attributed to the dislocation interaction with the precipitate which acts as the barrier to the dislocation motion on the slip plane. In order to achieve better understanding of critical events of dislocation motion and evolution of dislocation microstructure, we have developed numerical simulation method of dislocation-dislocation and dislocation-particle interactions by means of discrete dislocation dynamics at mesoscopic scale. In this work, Green’s function method is utilized for the computation of the stress fields of dislocation and misfitting particle, and the interaction forces acting on the dislocation. We also proposed the efficient algorithm of the connectivity vector for the dislocation line elements, linked-list data structure, to deal with the flexible interaction of dislocation line elements. The geometrical effect of dislocation slip planes on the dislocation bypassing behaviors is tested by changing the relative height of dislocation slip plane against the center plane of spherical particle, where cross slip event is also taken into account for the dislocation motion. Simulation results show a wide variety of topological changes of dislocation during motion on the slip planes around the particle, which results from the stress field of the particle varied with the relative height between the dislocation slip plane and center plane of particle. The full analysis of the mechanisms of dislocation line bypassing misfitting particle has been explained in this study.

• Periodical: Materials Science Forum (Volume 985)
• Pages: 35-41
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.985.35
• Online since: April 2020
• Authors: Jianbin Liu*, Shinji Muraishi
• Keywords: Dislocation Dynamics, Green Function, Misfitting Particle

References

[1] E. Orowan, Symposium on Internal Stresses in Metals and Alloys, Inst. Metals, London, 1948, p.451.

[2] Humphreys FJ, Hirsch PB. The deformation of single crystals of copper and copper-zinc alloys containing alumina particles Ⅱ. Microstructure and dislocation-particle interactions, Proc Roy Soc Lond A (1970), 318:73.

DOI: 10.1098/rspa.1970.0134

[3] N.M. Ghoniem and L.Z. Sun, Fast-sum method for the elastic field of three-dimensional dislocation ensembles, Phys. Review 60 (1999),128-140.

DOI: 10.1103/physrevb.60.128

[4] N.M. Ghoniem., Curved parametric segments for the stress field of 3-D dislocation loops. Trans. ASME J. Eng. Mater. Tech. 121(2), (1999), 136.

DOI: 10.1115/1.2812358

[5] Hirth J P and Lothe J, Theory of dislocations 2nd edn, 1982 (New York: wiley).

[6] T. Mura, Micromechanics of Defects in Solids 2nd, revised edition. Kluwer academic publishers, Boston,(1987).

[7] S. muraishi, Formulation of Eshelby's inclusion problem by BIEM (boundary integral equation method) and PDD (parametric dislocation dynamics). Mech. Mater 74, (2014), 41-55.

DOI: 10.1016/j.mechmat.2014.03.004

[8] Takahiro Hatano, Dynamics of a dislocation bypassing an impenetrable precipitate: The Hirsch mechanism revisited, Physical Review, B 74, (2006).

DOI: 10.1103/physrevb.74.020102

[9] Petr Paus, Jan Kratochvil, Michal Benes, A dislocation dynamics analysis of the critical cross-slip annihilation distance and the cyclic saturation stress in fcc single crystals at different temperatures, Acta Materialia, 61, (2013) 7917-7923.

DOI: 10.1016/j.actamat.2013.09.032

[10] M Rhee, H M Zbib, J P hirth, et al, Models for long-/short-range interactions and cross slip in 3D dislocation simulation of BCC single crystals, Modelling simul. Mater. Sci. Eng. 6 (1998), 467-492.

DOI: 10.1088/0965-0393/6/4/012

[11] Y. Xiang, D.J. Srolovitz, et al, Level set simulations of dislocation-particle bypass mechanisms, Acta Materialia, 52 (2004), 1745-1760.

DOI: 10.1016/j.actamat.2003.12.016