Phase transitions in shock-loaded titanium at pressures up to 150 GPa

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 $\alpha\to\omega$ conversion, and the second with melting. X-ray analysis revealed the presence of the $\omega$ phase in the samples in steel capsules recovered after loading at a pressure of 9–23 GPa. The dependence of the yield of the $\omega$ phase on the loading pressure has the form of a curve with a maximum at $\approx$ 15 GPa.