Concentration and Diffusion Characteristics of Interstitial C, O, N Atoms and Elastic Modulus in Vanadium and in V-4Cr-4Ti, V-W-Cr, V-Ta-Cr-Zr Alloys

摘要

The elastic (Young's) modulus and relaxation properties (amplitude-independent internal friction) of bcc metals and alloys (vanadium, V-4Cr-4Ti, V-W-Cr, and V-Ta-Cr-Zr alloys) have been studied in the temperature range of 25-400°C by means of dynamic mechanical spectroscopy within a low-frequency range (0.5-30.0 Hz). No carbon in vanadium and V-W-Cr alloy in solid-solution state is revealed. In the case of vanadium and V-W-Cr alloy, the solid-solution concentrations of oxygen and nitrogen and the diffusion characteristics thereof (diffusion activation energy, characteristic relaxation time, and the preexponen-tial factor in the diffusion equation) have been determined. In the case of V-4Cr-4Ti alloy, carbon, oxygen, and nitrogen solid solutions have not been observed. In V-Ta-Cr-Zr alloy, the solid-solution concentrations of interstitial atoms (C, O, N) are substantially lower than those in vanadium and V-W- Cr alloy. The values of elastic modulus in vanadium alloys can be either higher or lower than the elastic modulus inherent in vanadium depending on type of alloy (alloying) and on temperature. The V-4Ti-4Cr alloy exhibits the smallest value of the elastic modulus among all the materials under study. The temperature curves of the elastic (Young's) modulus for the studied materials exhibit no features, except for a slight local relaxation of the Young's modulus in the case of vanadium and V-W-Cr alloy in the temperature range of the relaxation peaks.