Ductile to brittle transition temperature of advanced tungsten alloys for nuclear fusion applications deduced by miniaturized three-point bending tests

Chao Yin, Dmitry Terentyev, Tao Zhang, Shuhei Nogami, Steffen Antusch, Chih Cheng Chang, Roumen H. Petrov, Thomas Pardoen

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

A large campaign of characterization of the ductile to brittle transition temperature (DBTT) and microstructure has been performed on several commercial and lab-scale pure tungsten grades, potassium doped tungsten alloys, and particle reinforced tungsten grades (with particles of TiC, Y2O3, or ZrC), all integrated in a large-scale neutron irradiation campaign. The DBTT is deduced based on miniaturized three-point bending tests to provide reference data for the assessment of the irradiation effects on the tungsten alloys. This miniaturized geometry is designed to minimize the operational cost of neutron irradiation, to speed up post-irradiation examination, and to reduce the amount of nuclear waste. The resulting DBTT ranges from around −15 up to 450 °C, depending on the material. The potassium doped tungsten alloys have the lowest DBTT, followed by rolled ZrC reinforced tungsten grade, commercial pure tungsten grades, lab-scale pure tungsten grades, and other particle reinforced tungsten grades. The crack plane orientation and microstructure with respect to grain shape and grain boundaries significantly affect the DBTT for forged/rolled tungsten products with elongated grains. The L-T orientation has a lower DBTT compared to the T-L orientation. Moreover, the DBTT difference in the L-T and T-L orientation raises with increasing the grain aspect ratio. An attempt is made to establish a relationship between the density of low and high angle grain boundaries and DBTT value. The obtained relationship is discussed in the frame of mechanical processing (i.e., rolling or forging) to optimize the DBTT by optimized manufacturing. The results are compared to recent computational predictions of the DBTT in tungsten.

Original languageEnglish
Article number105464
JournalInternational Journal of Refractory Metals and Hard Materials
Volume95
DOIs
Publication statusPublished - 2021 Feb

Keywords

  • Ductile to brittle transition temperature
  • Miniaturized three-point bending
  • Tungsten

ASJC Scopus subject areas

  • Ceramics and Composites
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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