The δ ′/δ phase transition in hafnium hydride and deuteride

Ken Kurosaki, Daichi Araki, Yuji Ohishi, Hiroaki Muta, Kenji Konashi, Shinsuke Yamanaka

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Bulk samples of hafnium (Hf) hydride and deuteride were prepared and the thermal properties, heat capacity (CP) and thermal conductivity (κ) were measured. In the CP-temperature curves for both samples, typical lambda-type peaks were observed at around 350 K, which was due to the second-order phase transition from the δ′-phase to the δ-phase. In Hf hydride, it is considered that the δ′-phase and the δ-phase consist of regularly arranged and randomly arranged hydrogen atoms, respectively. Therefore, it can be said that the δ′/δ phase transition observed in both Hf hydride and deuteride is an order-disorder phase transition. The values of κ as well as CP changed significantly at around the phase transition temperature.

Original languageEnglish
Pages (from-to)541-545
Number of pages5
JournalJournal of Nuclear Science and Technology
Issue number4
Publication statusPublished - 2015 Apr 3


  • fast reactor
  • hafnium deuteride
  • hafnium hydride
  • heat capacity
  • neutron control material
  • phase transition
  • thermal conductivity


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