Effects of temperature and microstructure on the elastic properties of selected Eu₂O₃-HfO₂ compositions

Thesis/Dissertation · Wed Oct 01 04:00:00 EDT 1975

DOI:https://doi.org/10.2172/4190874· OSTI ID:4190874

Suchomel, Robert Richard ^[1]

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1. Iowa State Univ., Ames, IA (United States)

Europium oxide is presently being tested for use as the control material in future nuclear power reactors. Elastic properties of europia and selected europia-rich compositions of the europia-hafnia system were investigated. The sonic technique was employed to measure elastic moduli from room temperature to 1500°C. Sintered monoclinic europia specimens were found to have uncommonly low room temperature moduli values and to exhibit hysteresis between heating and cooling curves because of the presence of microcracks caused by thermal expansion anisotropy. Fine grained hot pressed europia as well as sintered specimens that contained at least 6 mole percent hafnia did not exhibit these characteristics. Photomicrographs revealed that grain growth suppression was produced by and related to the amount of hafnia introduced. Hysteresis loops in the moduli versus temperature measurements were exhibited only by those specimens for which the average grain size was in excess of a critical value of 8 μm. Dilatometer measurements indicated that thermal expansion was relatively constant over the compositional range of interest.

• Research Organization: Ames Lab., Ames, IA (United States)
• Sponsoring Organization: US Energy Research and Development Administration (ERDA)
• DOE Contract Number: W-7405-ENG-82
• NSA Number: NSA-33-001091
• OSTI ID: 4190874
• Report Number(s): IS-T--678
• Country of Publication: United States
• Language: English

Related Subjects

*EUROPIUM OXIDES-- MICROSTRUCTURE
*HAFNIUM OXIDES-- MICROSTRUCTURE
36 MATERIALS SCIENCE
ANISOTROPY
BINARY MIXTURES
CRACKS
DILATOMETRY
GRAIN GROWTH
HIGH TEMPERATURE
HYSTERESIS
MEDIUM TEMPERATURE
MONOCLINIC LATTICES
SINTERED MATERIALS
THERMAL EXPANSION
VERY HIGH TEMPERATURE