Elastic and Relaxation Properties of V and Low-Activated V–W–Cr, V–W–Cr–Zr, V–Ta–Cr–Zr, and V–4Cr–4Ti Alloys

The elastic dynamic Young’s moduli (YM) and relaxation (amplitude-independent internal friction) properties of V and low-activated vanadium alloys (V–W–Cr, V–W–Cr–Zr, V–Ta–Cr–Zr, V–4Cr–4Ti) are studied in the frequency-temperature ranges (0.5–30.0 Hz, 25–400°C) and (100 kHz, –170–20°C). The diffusion parameters (diffusion activation energies, relaxation times, diffusion coefficients) and solid-solution concentrations of interstitial atoms C, O, N are determined for these materials. No solid solution of C is detected in V and alloys. No solid-solution concentration of O and N is detected in the V4–Cr4–Ti alloy. Zr alloying (V–W–Cr–Zr, V–Ta–Cr–Zr) significantly reduces the solid-solution concentration of interstitial elements O and N. In the alloys, the YM values can be both lower and higher than the YM values in V depending on the alloy type (alloying system, concentrations of C, O, N) and temperature. The lowest YM values are observed in the V-4Ti-4Cr alloy for all temperatures. The highest YM is found in the V–W–Cr–Zr alloy. In the room temperature range, the YM values obtained by low-frequency dynamic mechanical spectroscopy and ultrasonic resonance vibrations (100 kHz) are in good agreement (differences ≤2%). Approximating expressions for linear YM dependencies (without relaxation) are obtained for the materials under study. The number of YM defects increases with growing solid-solution concentration of O and N. The levels of dynamic drag of dislocations (viscous drag coefficients) which determine the brittleness of the studied materials are estimated. The V–Ta–Cr–Zr alloy is the least brittle.