An investigation of the microstructure and ductility of annealed cold-rolled tungsten

Chai Ren, Zhigang Zak Fang, Lei Xu, Jonathan P. Ligda, James D. Paramore, Brady G. Butler

Research output: Contribution to journalArticle

Abstract

Tungsten is notoriously brittle metal at room temperature. Furthermore, contrary to most metals, plastic deformation increases ductility and recrystallization decreases ductility of tungsten. The fundamentals that govern this behavior have challenged academia and industry for decades. This paper focuses on understanding the controlling factors of ductility through a systematic investigation of the changes in microstructure and mechanical properties of cold-rolled tungsten that occur during annealing. Cold-rolled tungsten samples were annealed at temperatures up to 1400 °C, and mechanical testing and microstructural analysis was performed before and after annealing. Furthermore, a dislocation mobility model based on the Orowan equation was applied. The mechanisms of deformation are discussed within the context of deformed and annealed microstructures. The high fraction of low angle grain boundaries and high density of edge dislocations were found to be the most important factors for ductility. Although there were gradual changes in microstructure and mechanical properties, the ductility of cold-rolled tungsten was maintained up to 1300 °C. The material recrystallized when annealed above this temperature, had no ductility, and suffered brittle fracture. Microstructural characterizations of the as-rolled material revealed a typical BCC texture, with grains elongated in rolling direction and a large amount of edge dislocations and low angle grain boundaries. The level of texturing and the fraction of low angle grain boundaries diminished after recrystallization. It was found that, compared to the recrystallized material, as-rolled tungsten can accommodate over 7 orders of magnitude higher deformation velocity due to the high density of edge dislocations.

LanguageEnglish (US)
Pages202-213
Number of pages12
JournalActa Materialia
Volume162
DOIs
StatePublished - Jan 1 2019

Fingerprint

Metal cladding
Metal analysis
Edge dislocations
Tungsten
Mechanical testing
Cold rolling
Ductility
Grain boundaries
Single crystals
Annealing
Mechanical properties
Microstructure
Metals
Texturing
Brittle fracture
Temperature
Plastic deformation
Textures

Keywords

  • Annealing
  • Ductility
  • Mechanical properties
  • Microstructure
  • Tungsten

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

Cite this

An investigation of the microstructure and ductility of annealed cold-rolled tungsten. / Ren, Chai; Fang, Zhigang Zak; Xu, Lei; Ligda, Jonathan P.; Paramore, James D.; Butler, Brady G.

In: Acta Materialia, Vol. 162, 01.01.2019, p. 202-213.

Research output: Contribution to journalArticle

Ren, Chai ; Fang, Zhigang Zak ; Xu, Lei ; Ligda, Jonathan P. ; Paramore, James D. ; Butler, Brady G. / An investigation of the microstructure and ductility of annealed cold-rolled tungsten. In: Acta Materialia. 2019 ; Vol. 162. pp. 202-213.
@article{94b9219dd4c349b2bcc304dc1739a2a0,
title = "An investigation of the microstructure and ductility of annealed cold-rolled tungsten",
abstract = "Tungsten is notoriously brittle metal at room temperature. Furthermore, contrary to most metals, plastic deformation increases ductility and recrystallization decreases ductility of tungsten. The fundamentals that govern this behavior have challenged academia and industry for decades. This paper focuses on understanding the controlling factors of ductility through a systematic investigation of the changes in microstructure and mechanical properties of cold-rolled tungsten that occur during annealing. Cold-rolled tungsten samples were annealed at temperatures up to 1400 °C, and mechanical testing and microstructural analysis was performed before and after annealing. Furthermore, a dislocation mobility model based on the Orowan equation was applied. The mechanisms of deformation are discussed within the context of deformed and annealed microstructures. The high fraction of low angle grain boundaries and high density of edge dislocations were found to be the most important factors for ductility. Although there were gradual changes in microstructure and mechanical properties, the ductility of cold-rolled tungsten was maintained up to 1300 °C. The material recrystallized when annealed above this temperature, had no ductility, and suffered brittle fracture. Microstructural characterizations of the as-rolled material revealed a typical BCC texture, with grains elongated in rolling direction and a large amount of edge dislocations and low angle grain boundaries. The level of texturing and the fraction of low angle grain boundaries diminished after recrystallization. It was found that, compared to the recrystallized material, as-rolled tungsten can accommodate over 7 orders of magnitude higher deformation velocity due to the high density of edge dislocations.",
keywords = "Annealing, Ductility, Mechanical properties, Microstructure, Tungsten",
author = "Chai Ren and Fang, {Zhigang Zak} and Lei Xu and Ligda, {Jonathan P.} and Paramore, {James D.} and Butler, {Brady G.}",
year = "2019",
month = "1",
day = "1",
doi = "10.1016/j.actamat.2018.10.002",
language = "English (US)",
volume = "162",
pages = "202--213",
journal = "Acta Materialia",
issn = "1359-6454",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - An investigation of the microstructure and ductility of annealed cold-rolled tungsten

AU - Ren, Chai

AU - Fang, Zhigang Zak

AU - Xu, Lei

AU - Ligda, Jonathan P.

AU - Paramore, James D.

AU - Butler, Brady G.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Tungsten is notoriously brittle metal at room temperature. Furthermore, contrary to most metals, plastic deformation increases ductility and recrystallization decreases ductility of tungsten. The fundamentals that govern this behavior have challenged academia and industry for decades. This paper focuses on understanding the controlling factors of ductility through a systematic investigation of the changes in microstructure and mechanical properties of cold-rolled tungsten that occur during annealing. Cold-rolled tungsten samples were annealed at temperatures up to 1400 °C, and mechanical testing and microstructural analysis was performed before and after annealing. Furthermore, a dislocation mobility model based on the Orowan equation was applied. The mechanisms of deformation are discussed within the context of deformed and annealed microstructures. The high fraction of low angle grain boundaries and high density of edge dislocations were found to be the most important factors for ductility. Although there were gradual changes in microstructure and mechanical properties, the ductility of cold-rolled tungsten was maintained up to 1300 °C. The material recrystallized when annealed above this temperature, had no ductility, and suffered brittle fracture. Microstructural characterizations of the as-rolled material revealed a typical BCC texture, with grains elongated in rolling direction and a large amount of edge dislocations and low angle grain boundaries. The level of texturing and the fraction of low angle grain boundaries diminished after recrystallization. It was found that, compared to the recrystallized material, as-rolled tungsten can accommodate over 7 orders of magnitude higher deformation velocity due to the high density of edge dislocations.

AB - Tungsten is notoriously brittle metal at room temperature. Furthermore, contrary to most metals, plastic deformation increases ductility and recrystallization decreases ductility of tungsten. The fundamentals that govern this behavior have challenged academia and industry for decades. This paper focuses on understanding the controlling factors of ductility through a systematic investigation of the changes in microstructure and mechanical properties of cold-rolled tungsten that occur during annealing. Cold-rolled tungsten samples were annealed at temperatures up to 1400 °C, and mechanical testing and microstructural analysis was performed before and after annealing. Furthermore, a dislocation mobility model based on the Orowan equation was applied. The mechanisms of deformation are discussed within the context of deformed and annealed microstructures. The high fraction of low angle grain boundaries and high density of edge dislocations were found to be the most important factors for ductility. Although there were gradual changes in microstructure and mechanical properties, the ductility of cold-rolled tungsten was maintained up to 1300 °C. The material recrystallized when annealed above this temperature, had no ductility, and suffered brittle fracture. Microstructural characterizations of the as-rolled material revealed a typical BCC texture, with grains elongated in rolling direction and a large amount of edge dislocations and low angle grain boundaries. The level of texturing and the fraction of low angle grain boundaries diminished after recrystallization. It was found that, compared to the recrystallized material, as-rolled tungsten can accommodate over 7 orders of magnitude higher deformation velocity due to the high density of edge dislocations.

KW - Annealing

KW - Ductility

KW - Mechanical properties

KW - Microstructure

KW - Tungsten

UR - http://www.scopus.com/inward/record.url?scp=85054457457&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85054457457&partnerID=8YFLogxK

U2 - 10.1016/j.actamat.2018.10.002

DO - 10.1016/j.actamat.2018.10.002

M3 - Article

VL - 162

SP - 202

EP - 213

JO - Acta Materialia

T2 - Acta Materialia

JF - Acta Materialia

SN - 1359-6454

ER -