Defect characterization, mechanical and thermal property evaluation in CVD-W after low-dose neutron irradiation

Xiaoou Yi, Lei Zhang, Wentuo Han, Jiao Chen, Pingping Liu, Yanwei Lv, Jiupeng Song, Luwei Xue, Diancheng Geng, Kenta Yoshida, Takeshi Toyama, Qian Zhan, Farong Wan, Somei Ohnuki, Yasuyoshi Nagai

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Ultra-high purity (> 99.9999 wt%) chemical vapour deposited tungsten (CVD–W) samples were neutron irradiated in the BR2 reactor (Belgium) at Tirr < 210 °C to ~ 0.15 dpa, followed by isochronal annealing at 500, 800 and 1100 °C. Defect characterization showed that dislocation loops dominated the as-irradiated damage microstructure and were mostly ≤5 nm. Void formation was observed after post-irradiation annealing at 1100 °C. The mechanical and thermal properties of CVD-W were evaluated based on tensile tests, Vickers hardness and temperature wave analysis. Fractography study suggested that a transition from intergranular fracture to cleavage fracture took place in the material after neutron irradiation. Hardening was found ~ 23% after irradiation. Subsequent annealing below 800 °C saw further increase in hardness, featuring a maximum value of about Hv = 487. Softening occurred at 1100 °C. Thermal diffusivity dropped by ~ 65% after irradiation and ~ 40% of this degradation recovered at 1100 °C.

Original languageEnglish
Article number105004
JournalInternational Journal of Refractory Metals and Hard Materials
Volume85
DOIs
Publication statusPublished - 2019 Dec

Keywords

  • CVD-W
  • Defects
  • Mechanical properties
  • Neutron irradiation
  • Thermal properties

ASJC Scopus subject areas

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

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