[3J10-15] Zirconium Alloys

[3J13] The hardness value evaluation with hydride generations in Zr by the nano-indentation hardness test and dynamic microstructure observation

*Kouichi Tougou¹, Takashi Onitsuka¹, Kaoru Tone¹, Naohiro Shimomura¹, Ken-ichi Fukumoto¹, Masayoshi Uno¹, Hiroaki Muta² (1. University of Fukui, 2. Osaka University)

Keywords:Hydride, Hardness value, Slip plane of dislocation, In-situ TEM observation during tensile test, Nano-indentation hardness test, Dynamic microstructure observation

In the zircaloy of fuel cladding tube, the habit planes of hydrides and the slip planes of dislocation were reported from the previous work, and the difference of degree of hardening was guessed by these differences. In this study, in order to investigate that the hardness values were affected by the difference between the habit planes of δ hydrides and the slip planes of dislocation, the δ hydrides were generated in pure Zr. The difference of slip planes of dislocation with the difference of tensile directions in pure Zr specimen and the difference of the hardness values by the change of slip plane of dislocation were evaluated by the in-situ TEM observation during tensile test and the nano-indentation hardness test. The in-situ TEM observation during tensile test was performed that the incident directions of electron beam were corresponded to the {2-1-10} plane. In the case when the tensile axis was approximately 50 degrees or more from the <01-10> direction, the (0001) plane slip and {10-11} plane slip were mainly observed, and in the case when the tensile axis was less than approximately 50 degrees from that, the {1-100} plane slip was mainly observed.