Phase Transitions in Shock-Loaded Titanium at Pressures up to 150 GPa
V. A. Borisenoka, M. V. Zhernokletova, b, A. E. Kovalevb, A. M. Poduretsa, b, V. G. Simakova, b, M. I. Tkachenkob
a Sarov Physical-Technical Institute of National Research Nuclear University “MEPhI”
Sarov, 607186 Russia
b Institute of Physics of Explosion, Institute of Experimental Physics (VNIIEF), Federal Nuclear Center
Sarov, 607188 Russia
Keywords: titanium, Hugoniot, phase transition, melting, speed of sound
Abstract
Phase transformations in VT1-0 titanium were studied. Shock profiles in the pressure range of 10–26 GPa were recorded by polyvinylidene fluoride sensors. Sound velocities in shock-compressed titanium samples were measured by two methods. At a pressure less than 30 GPa, the speed of sound in titanium was determined by the counter unloading method using Manganin gauges, and at a pressure of 30–150 GPa, it was determined by the overtaking unloading method using indicator liquids. At a pressure of 20–40 and 60–90 GPa, the pressure dependences of the speed of sound have breaks, the first of which is apparently associated with the α → ω conversion, and the second with melting. X-ray analysis revealed the presence of the ω phase in the samples in steel capsules recovered after loading at a pressure of 9–23 GPa. The dependence of the yield of the ω phase on the loading pressure has the form of a curve with a maximum at ≈15 GPa.
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