Hostname: page-component-8448b6f56d-xtgtn Total loading time: 0 Render date: 2024-04-18T01:21:58.719Z Has data issue: false hasContentIssue false
  • English
  • Français

Mechanics and Dislocation Structures at the Micro-Scale: Insights on Dislocation Multiplication Mechanisms from Discrete Dislocation Dynamics Simulations

Published online by Cambridge University Press:  04 April 2014

D. Weygand
D. Weygand*
Affiliation:
Institute for Applied Materials, Karlsruhe Institute of Technology, Kaiserstr. 12, 76131 Karlsruhe, Germany
Get access

Abstract

The plasticity of micro-pillar deformation has widely been studied by discrete dislocation dynamics simulations to explain the so-called size effect. In this study the role of glissile junctions forming during plastic deformation under various loading scenarios is in the center of interest. The activity of these naturally forming dislocation sources is followed in detail. Surprisingly these junctions are rather active sources and not just another obstacle as often assumed. Their relative contribution to the overall dislocation density for the simulated specimens reaches often values of 20% or even more. The formation of such a glissile junction is often correlated to stress drops or the end of a stress drop. It is therefore suggested – at least for the sample sizes considered – that this dislocation multiplication mechanism should be take into account in continuum models such as crystal plasticity of higher order dislocation continuum theories.

Keywords

dislocationsstrengthsimulation
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1651: Symposium KK – Dislocation Plasticity , 2014 , mrsf13-1651-kk07-02
Copyright
Copyright © Materials Research Society 2014 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Uchic, M.D. et al. . Sample Dimensions Influence Strength and Crystal Plasticity. Science, Vol. 305 (2004) 986.CrossRefGoogle Scholar
Weygand, D., Size Effect in the Plastic response of sub-micrometer sized pillars: A three-dimensional discrete dislocation dynamics study, Proceedings of 3rd International Conference on Multiscale materials Modeling (2006) 244.Google Scholar
Parthasarathy, A., Rao, S.I., Dimiduk, D.M., Uchic, M.D., Trinkle, D.R., Contributions to size effect of yield strength from the stochastics of dislocations source length in finite samples, Scripta Mater. 57 (2007) 313.CrossRefGoogle Scholar
Senger, J., Weygand, D., Gumbsch, P., Kraft, O., Discrete dislocation simulations of the plasticity of micro-pillars under uniaxial loading, Scripta Materialia 58 (2008) 587.CrossRefGoogle Scholar
Uchic, M.D. et al. . Plasticity of Micrometer-Scale Single Crystals in Compression. Annual Review of Materials Research, Vol. 39 (2009) 361.CrossRefGoogle Scholar
Kraft, O., Gruber, P., Mönig, R., Weygand, D., Plasticity in Confined Dimensions. Annual Review of Materials Research, Vol. 40 (2010) 293.CrossRefGoogle Scholar
Weygand, D., Poignant, M., Gumbsch, P., Kraft, O., Three-dimensional dislocation dynamics simulation of the influence of sample size on the stress-strain behavior of fcc single-crystalline pillars, Mat. Sci. Eng A 483-484 (2008) 188.CrossRefGoogle Scholar
Motz, C., Weygand, D., Senger, J., Gumbsch, P., Initial dislocation structures in 3-D discrete dislocation dynamics and their influence on microscale plasticity, Acta Materialia 57 (2009) 1744.CrossRefGoogle Scholar
Senger, J., Weygand, D., Motz, C., Gumbsch, P., Kraft, O., Aspect ratio and stochastic effects in the plasticity of uniformly loaded micrometer sized specimens, Acta. Materialia 59 (2011) 2937.CrossRefGoogle Scholar
Senger, J., Weygand, D., Kraft, O., Gumbsch, P., Dislocation microstructure evolution in cyclically twisted micro samples: a Discrete Dislocation Dynamics simulation, Mod. Sim. Mat. Sci. Eng. (2011) 074004.CrossRefGoogle Scholar
Weygand, D., Friedman, L.H., Van der Giessen, E., Needleman, A., Aspects of boundary-value problem solutions with three-dimensional dislocation dynamics, Mod. Sim. Mat. Sci. Eng. 10 (2002) 437.CrossRefGoogle Scholar
Weygand, D., Senger, J., Motz, C., Augustin, W., Heuveline, V., Gumbsch, P., High Performance Computing and Discrete Dislocation Dynamics: Plasticity of Micrometer Sized Specimens, High Performance Computing In Science And Engineering '08 ed: Nagel WE; Kroner DB; Resch MM, Springer (2009) 507. CrossRefGoogle Scholar
Weygand, D., Gumbsch, P., Study of dislocation reactions and rearrangements under different loading conditions, Mat. Sci. Eng. A 400-401 (2005) 158.CrossRefGoogle Scholar
Saada, G., Veyssiere, P., Work hardening of Face Centred Cubic Crystals. Dislocation Intersection and Cross Slip, Dislocations in Solids, Chap 61, ed. Nabarro, and Duesbery, , Elsevier, (2002) 413.Google Scholar
Madec, R., Devincre, B., Kubin, L., Hoc, T., Rodney, D., The Role of Collinear Interaction in Dislocation-Induced Hardening, Science 2003, 1879.CrossRefGoogle ScholarPubMed
Devincre, B., Kubin, L., Hoc, T., Physical analysis of crystal plasticity by DD simulations, Scripta Materialia 54 (2006) 741.CrossRefGoogle Scholar
Csikor, F.F., Motz, C., Weygand, D., Zaiser, M., Zapperi, S., Dislocation Avalanches, Strain Bursts, and the Problem of Plastic Forming at the Micrometer Scale, Science 318 (2007) 251.CrossRefGoogle ScholarPubMed