Grain boundary effect on nanoindentation: A multiscale discrete dislocation dynamics model

Journal article
(Original article)


Publication Details

Author(s): Zaiser M, Lu S, Zhang B, Li X, Zhao J, Zaiser M, Fan H, Zhang X
Journal: Journal of the Mechanics and Physics of Solids
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Publication year: 2019
Volume: 126
Pages range: 117-135
ISSN: 0022-5096


Abstract

Nanoindentation is a convenient method to investigate the mechanical properties of materials on small scales by utilizing low loads and small indentation depths. However, the effect of grain boundaries (GBs) on the nanoindentation response remains unclear and needs to be studied by investigating in detail the interactions between dislocations and GBs during nanoindentation. In the present work, we employ a three-dimensional multi scale modeling framework, which couples three-dimensional discrete dislocation dynamics (DDD) with the Finite Element method (FEM) to investigate GB effects on the nanoindentation behavior of an aluminum bicrystal. The interaction between dislocations and GB is physically modeled in terms of a penetrable GB, where piled-up dislocations can penetrate through the GB and dislocation debris at GBs can emit full dislocations into grains. In the simulation, we confirmed two experimentally observed phenomena, namely, pop-in events and the dependence of indentation hardness on the distance from GB. Two pop in events were observed, of which the initial pop-in event is correlated with the activation and multiplication of dislocations, while the GB pop-in event results from dislocation transmission through the GB. By changing the distance between the indenter and GB, the simulation shows that the indentation hardness increases with decreasing GB-indenter distance. A quantitative model has been formulated which relates the dependency of indentation hardness on indentation depth and on GB-indenter distance to the back stress created by piled-up geometrically necessary dislocations in the plastic zone and to the additional constraint imposed by the GB on the plastic zone size. (C) 2019 Elsevier Ltd. All rights reserved.


FAU Authors / FAU Editors

Zaiser, Michael Prof. Dr.
Lehrstuhl für Werkstoffsimulation


External institutions with authors

Sichuan University (SCU) / 四川大学
Southwest Jiaotong University / 西南交通大学


How to cite

APA:
Zaiser, M., Lu, S., Zhang, B., Li, X., Zhao, J., Zaiser, M.,... Zhang, X. (2019). Grain boundary effect on nanoindentation: A multiscale discrete dislocation dynamics model. Journal of the Mechanics and Physics of Solids, 126, 117-135. https://dx.doi.org/10.1016/j.jmps.2019.02.003

MLA:
Zaiser, Michael, et al. "Grain boundary effect on nanoindentation: A multiscale discrete dislocation dynamics model." Journal of the Mechanics and Physics of Solids 126 (2019): 117-135.

BibTeX: 

Last updated on 2019-24-05 at 11:23