Internal length scale and grain boundary yield strength in gradient models of polycrystal plasticity: How do they relate to the dislocation microstructure?

Zhang X, Aifantis KE, Senger J, Weygand D, Zaiser M (2014)

Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2014

Journal

Journal of Materials Research Cambridge University Press (CUP) / Materials Research Society

Publisher: Cambridge University Press (CUP) / Materials Research Society

Book Volume: 29

Pages Range: 2116-2128

Journal Issue: 18

DOI: 10.1557/jmr.2014.234

Abstract

Gradient plasticity provides an effective theoretical framework to interpret heterogeneous and irreversible deformation processes on micron and submicron scales. By incorporating internal length scales into a plasticity framework, gradient plasticity gives access to size effects, strain heterogeneities at interfaces, and characteristic lengths of strain localization. To relate the magnitude of the internal length scale to parameters of the dislocation microstructure of the material, 3D discrete dislocation dynamics (DDD) simulations were performed for tricrystals of different dislocation source lengths (100, 200, and 300 nm). Comparing the strain profiles deduced from DDD with gradient plasticity predictions demonstrated that the internal length scale depends on the flow-stress-controlling mechanism. Different dislocation mechanisms produce different internal lengths. Furthermore, by comparing a gradient plasticity framework with interfacial yielding to the simulations it was found that, even though in the DDD simulations grain boundaries (GBs) were physically impenetrable to dislocations, on the continuum scale the assumption of plastically deformable GBs produces a better match of the DDD data than the assumption of rigid GBs. The associated effective GB strength again depends on the dislocation microstructure in the grain interior.

Authors with CRIS profile

Michael Zaiser Lehrstuhl für Werkstoffsimulation

Involved external institutions

Southwest Jiaotong University / 西南交通大学 CN China (CN) Aristotle University of Thessaloniki GR Greece (GR) Karlsruhe Institute of Technology (KIT) DE Germany (DE)

How to cite

APA:

Zhang, X., Aifantis, K.E., Senger, J., Weygand, D., & Zaiser, M. (2014). Internal length scale and grain boundary yield strength in gradient models of polycrystal plasticity: How do they relate to the dislocation microstructure? Journal of Materials Research, 29(18), 2116-2128. https://dx.doi.org/10.1557/jmr.2014.234

MLA:

Zhang, Xu, et al. "Internal length scale and grain boundary yield strength in gradient models of polycrystal plasticity: How do they relate to the dislocation microstructure?" Journal of Materials Research 29.18 (2014): 2116-2128.

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