Strength enhancement induced by grain boundary solute segregations in ultrafine-grained alloys

Research outputpeer-review

Abstract

A model is proposed explaining enhanced strength of ultrafine-grained alloys that contain grain boundary (GB) solute segregations. In the framework of the proposed model these segregations are treated as homogeneous ellipsoidal inclusions and act as the sources of elastic stresses affecting the emission of lattice dislocations from GBs. These segregations pin the ends of lattice dislocation segments at the initial stage of dislocation propagation along GBs, and the unpinning requires a load increase, leading to the enhanced yield strength. We calculate the contribution of GB segregations to the yield strength for the ultrafine-grained 1570 Al alloy. We demonstrate that the maximum yield strength of this alloy is achieved in the case of clustered, nearly spherical Mg segregations with a high Mg concentration and a diameter to thickness ratio of 1.0-1.4, depending on the Mg concentration inside segregations. We also briefly discuss the possible role of GB dislocations in the formation of such concentrated solute segregations as well as the influence of GB segregations on the strengthening of alloys containing nanoscale twins. The results of the calculations agree well with experimental data.

Original languageEnglish
JournalInternational Journal of Plasticity
DOIs
Publication statusPublished - 1 Jan 2019

Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

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title = "Strength enhancement induced by grain boundary solute segregations in ultrafine-grained alloys",
abstract = "A model is proposed explaining enhanced strength of ultrafine-grained alloys that contain grain boundary (GB) solute segregations. In the framework of the proposed model these segregations are treated as homogeneous ellipsoidal inclusions and act as the sources of elastic stresses affecting the emission of lattice dislocations from GBs. These segregations pin the ends of lattice dislocation segments at the initial stage of dislocation propagation along GBs, and the unpinning requires a load increase, leading to the enhanced yield strength. We calculate the contribution of GB segregations to the yield strength for the ultrafine-grained 1570 Al alloy. We demonstrate that the maximum yield strength of this alloy is achieved in the case of clustered, nearly spherical Mg segregations with a high Mg concentration and a diameter to thickness ratio of 1.0-1.4, depending on the Mg concentration inside segregations. We also briefly discuss the possible role of GB dislocations in the formation of such concentrated solute segregations as well as the influence of GB segregations on the strengthening of alloys containing nanoscale twins. The results of the calculations agree well with experimental data.",
keywords = "Dislocations, Grain boundary segregations, Inhomogeneous materials, Strengthening mechanisms",
author = "Bobylev, {S. V.} and Enikeev, {N. A.} and Sheinerman, {A. G.} and Valiev, {R. Z.}",
year = "2019",
month = "1",
day = "1",
doi = "10.1016/j.ijplas.2019.07.013",
language = "English",
journal = "International Journal of Plasticity",
issn = "0749-6419",
publisher = "Elsevier",

}

TY - JOUR

T1 - Strength enhancement induced by grain boundary solute segregations in ultrafine-grained alloys

AU - Bobylev, S. V.

AU - Enikeev, N. A.

AU - Sheinerman, A. G.

AU - Valiev, R. Z.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - A model is proposed explaining enhanced strength of ultrafine-grained alloys that contain grain boundary (GB) solute segregations. In the framework of the proposed model these segregations are treated as homogeneous ellipsoidal inclusions and act as the sources of elastic stresses affecting the emission of lattice dislocations from GBs. These segregations pin the ends of lattice dislocation segments at the initial stage of dislocation propagation along GBs, and the unpinning requires a load increase, leading to the enhanced yield strength. We calculate the contribution of GB segregations to the yield strength for the ultrafine-grained 1570 Al alloy. We demonstrate that the maximum yield strength of this alloy is achieved in the case of clustered, nearly spherical Mg segregations with a high Mg concentration and a diameter to thickness ratio of 1.0-1.4, depending on the Mg concentration inside segregations. We also briefly discuss the possible role of GB dislocations in the formation of such concentrated solute segregations as well as the influence of GB segregations on the strengthening of alloys containing nanoscale twins. The results of the calculations agree well with experimental data.

AB - A model is proposed explaining enhanced strength of ultrafine-grained alloys that contain grain boundary (GB) solute segregations. In the framework of the proposed model these segregations are treated as homogeneous ellipsoidal inclusions and act as the sources of elastic stresses affecting the emission of lattice dislocations from GBs. These segregations pin the ends of lattice dislocation segments at the initial stage of dislocation propagation along GBs, and the unpinning requires a load increase, leading to the enhanced yield strength. We calculate the contribution of GB segregations to the yield strength for the ultrafine-grained 1570 Al alloy. We demonstrate that the maximum yield strength of this alloy is achieved in the case of clustered, nearly spherical Mg segregations with a high Mg concentration and a diameter to thickness ratio of 1.0-1.4, depending on the Mg concentration inside segregations. We also briefly discuss the possible role of GB dislocations in the formation of such concentrated solute segregations as well as the influence of GB segregations on the strengthening of alloys containing nanoscale twins. The results of the calculations agree well with experimental data.

KW - Dislocations

KW - Grain boundary segregations

KW - Inhomogeneous materials

KW - Strengthening mechanisms

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U2 - 10.1016/j.ijplas.2019.07.013

DO - 10.1016/j.ijplas.2019.07.013

M3 - Article

JO - International Journal of Plasticity

JF - International Journal of Plasticity

SN - 0749-6419

ER -