Effects of hydrogen and oxygen on the elastic moduli of vanadium, niobium, and tantalum single crystals

Journal Article · Wed Apr 16 04:00:00 EDT 1975 · Phys. Status Solidi (a), v. 28, no. 2, pp. 591-602

DOI:https://doi.org/10.1002/pssa.2210280225· OSTI ID:4200625

Fisher, E S; Westlake, D G; Ockers, S T

Measurements of the ultrasonic wave velocities at 30 to 50 MHz frequencies reveal very significant effects of dissolved hydrogen on the elastic shear moduli, C' = (C$sub 11$ -- C$sub 12$)/2 and C$sub 44$, of the group V bcc transition metals. In all cases, C' decreases with increasing hydrogen solute, whereas C$sub 44$ increases and the bulk modulus remains nearly constant. The $delta$C' effect is interpreted as a Snoek relaxation that arises from a tetragonal elastic dipole produced by interstitial hydrogen in tetrahedral sites. The data indicate that the tetragonal distortion parameter, lambda$sub 1$ - lambda$sub 2$, is 0.11 for V, 0.051 for Nb, and 0.047 for Ta. The rate of increase in C$sub 44$ is 0.5 percent per at. percent hydrogen for V, 1.8 percent for Nb, and 0.13 percent for Ta. This increase is reflected in a positive change in the isotropic Young's modulus for Nb, opposing the Snoek relaxation effect. The addition of oxygen to V and Nb produces no Snoek relaxation at these high frequencies, but the positive change in C$sub 44$ is as pronounced as in the hydrogen addition. Present information is not sufficient to relate this $delta$$C$$sub 44$ effect strictly to the interstitial solute configuration. (auth)

• Research Organization: Argonna National Lab., IL
• NSA Number: NSA-33-003561
• OSTI ID: 4200625
• Journal Information: Phys. Status Solidi (a), v. 28, no. 2, pp. 591-602, Journal Name: Phys. Status Solidi (a), v. 28, no. 2, pp. 591-602; ISSN PSSAB
• Country of Publication: Germany
• Language: English

Related Subjects

360103* --Materials--Metals & Alloys--Mechanical Properties
HYDROGEN ADDITIONS
MONOCRYSTALS
N50230* --Metals
Ceramics
& Other Materials--Metals & Alloys--Properties
Structure & Phase Studies
NIOBIUM
OXYGEN ADDITIONS
RELAXATION
TANTALUM
YOUNG MODULUS VANADIUM