Rate-controlling deformation mechanisms in drawn tungsten wires

Maximilian Fuhr*, Till Höschen, Johann Riesch, Max Boleininger, Jürgen Almanstötter, Wolfgang Pantleon, Rudolf Neu

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Undeformed tungsten suffers from a brittleness that makes it unsuitable for applications at low temperatures. Cold-worked tungsten materials such as drawn wires or rolled plates can however show considerable ductility even at low temperatures. The reason for this behaviour is so far not understood. We investigated a series of potassium-doped tungsten wires that were subsequently drawn from one sintered ingot, making them chemically identical. Hence, the properties of the wires could be studied without the influence of different impurity levels. Using transient mechanical tests, namely repeated stress relaxation experiments and strain-rate jump tests, the effective activation volumes (Formula presented.) and strain-rate sensitivities m of the wires were determined at room-temperature. Based on the obtained results, it is deduced that the motion of (Formula presented.) screw dislocations by formation and dissociation of kink-pairs is controlling the rate of plastic deformation in all wires that show plasticity at room temperature. It is hence concluded that the ductility of drawn tungsten wires at low temperatures is not due to a change in the rate-controlling deformation mechanisms, but should be a consequence of the microstructural and textural changes during wire drawing.
Original languageEnglish
JournalPhilosophical Magazine
Volume103
Issue number11
Pages (from-to)1029-1047
ISSN1478-6435
DOIs
Publication statusPublished - 2023

Keywords

  • Tungsten wires
  • Activation volume
  • Kink-pair mechanism
  • Strain-rate sensitivity

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