J. Phys. IV France
Volume 134, August 2006
EURODYMAT 2006 - 8th International Conference on Mechanical and Physical Behaviour of Materials under Dynamic Loading
Page(s) 971 - 976
Publié en ligne 26 juillet 2006
EURODYMAT 2006 - 8th International Conference on Mehanical and Physical Behaviour of Materials under Dynamic Loading
J. Cirne, R. Dormeval, et al.
J. Phys. IV France 134 (2006) 971-976

DOI: 10.1051/jp4:2006134148

Dynamic strength of uranium at high temperatures

E. Zaretsky1, B. Herrmann2 and D. Shvarts2

1  Mechanical Engineering Dept., Ben Gurion University, PO Box 653, Beer-Sheva, Israel
2  Nuclear Research Center - Negev, PO Box 9001, Beer-Sheva, Israel

Published online: 26 July 2006

Unalloyed uranium (PU) and uranium-0.78 wt% Ti alloy (UT) were studied in VISAR-monitored planar impact experiments with initial sample temperatures ranged from 27$^{\circ}$C to 860$^{\circ}$C. The recorded waveforms was used for obtaining the stress-strain $\sigma
(\varepsilon )$ and deviator stress-strain $s(\varepsilon)$ diagrams, the conventional elastic limit Y0.2, and the spall strength of the alloys at different testing temperatures. The strengths Y0.2 of both the materials stay almost constant up to the temperature of $\alpha -\beta$ transformation, increase strongly in the $\beta$-phase domain, and abruptly drop above the temperature of $\beta -\gamma $ transformation. The temperature dependences of the spall strength of alloys differ from those of the compressive strengths indicating the prevailing role of the void nucleation (over the void growth) in the spallation process. The most striking finding of the work is the existence of $\rm beta$-uranium at pressures some 3 GPa higher than that permitted thermodynamically. The life time and the borders of existence of this non-equilibrium phase are unknown and should be determined in future.

© EDP Sciences 2006