Dislocation dynamics in heterogeneous nanostructured materials

Shuozhi Xu, Justin Y Cheng, Nathan A. Mara, Irene J. Beyerlein

Research output: Contribution to journalArticlepeer-review

Abstract

Crystalline materials can be strengthened by introducing dissimilar phases that impede dislocation glide. At the same time, the changes in microstructure and chemistry usually make the materials less ductile. One way to circumvent the strength–ductility dilemma is to take advantage of heterogeneous nanophases which simultaneously serve as dislocation barriers and sources. Owing to their superior mechanical properties, heterogeneous nanostructured materials (HNMs) have attracted a lot of attention worldwide. Nevertheless, it has been difficult to characterize dislocation dynamics in HNMs using classical continuum models, mainly due to the challenges in describing the elastic and plastic heterogeneity among the phases. In this work, we advance a phase-field dislocation dynamics (PFDD) model to treat multi-phase materials, consisting of phases differing in composition, structural order, and size in the same system. We then apply the advanced PFDD model to exploring two important but divergent materials design problems in HNMs: dislocation/obstacle interactions and dislocation/interface interactions. Results show that the interactions between a dislocation and distribution of obstacles varying in structure and composition cannot be understood by simply interpolating from their individual interactions with a dislocation. It is also found that materials containing interfaces with nanoscale thicknesses and compositional gradients have a much higher dislocation bypass stress than those with sharp interfaces, providing an explanation for the simultaneous high strength and toughness of thick interface-containing nanolaminates as observed in recent experiments.

Original languageEnglish (US)
Article number105031
JournalJournal of the Mechanics and Physics of Solids
Volume168
DOIs
StatePublished - Nov 2022

Bibliographical note

Funding Information:
We thank Dr. Youxing Chen and Ms. Ashley Roach for helpful discussions. The authors gratefully acknowledge financial support from the Department of Energy, Office of Science, Basic Energy Sciences Program DE-SC0020133. JYC is supported in part by DOE NNSA SSGF under cooperative agreement number DE-NA0003960. Use was made of computational facilities purchased with funds from the National Science Foundation, USA (CNS-1725797) and administered by the Center for Scientific Computing (CSC). The CSC is supported by the California NanoSystems Institute and the Materials Research Science and Engineering Center (MRSEC; NSF DMR 1720256) at UC Santa Barbara. JYC and NAM acknowledge the Minnesota Supercomputing Institute at the University of Minnesota (http://www.msi.umn.edu) for providing resources that contributed to the research results reported within this paper.

Funding Information:
We thank Dr. Youxing Chen and Ms. Ashley Roach for helpful discussions. The authors gratefully acknowledge financial support from the Department of Energy, Office of Science, Basic Energy Sciences Program DE-SC0020133 . JYC is supported in part by DOE NNSA SSGF under cooperative agreement number DE-NA0003960 . Use was made of computational facilities purchased with funds from the National Science Foundation, USA ( CNS-1725797 ) and administered by the Center for Scientific Computing (CSC) . The CSC is supported by the California NanoSystems Institute and the Materials Research Science and Engineering Center (MRSEC; NSF DMR 1720256 ) at UC Santa Barbara. JYC and NAM acknowledge the Minnesota Supercomputing Institute at the University of Minnesota ( http://www.msi.umn.edu ) for providing resources that contributed to the research results reported within this paper.

Publisher Copyright:
© 2022 Elsevier Ltd

Keywords

  • Dislocation dynamics
  • Heterogeneous materials
  • Nanolaminates
  • Phase-field method

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