Hydrogen Behavior in Metals Using Nuclear Magnetic Resonance.
Final scientific rept. Mar 66-Nov 70,
ISRAEL ATOMIC ENERGY COMMISSION YAVNE SOREQ NUCLEAR RESEARCH CENTRE
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Parameters considered important for the explanation of hydrogen embrittlement of titanium and its alloys have been measured using NMR techniques. The proton spin lattice relaxation time T1 has been measured by the pulse technique at 19.00 MHz as a function of temperature in the range 25-500C for a series of samples in the alpha, beta, gamma phases of titanium hydride. The diffusional activation energy was found to be constant with respect to the hydrogen concentration. The activation energy behavior and jump attempt frequency is discussed in relation to a harmonic oscillator potential well derived from neutron inelastic scattering experiments and from this study. The conduction electron contribution to the relaxation mechanism increased with hydrogen concentration, indicating an increase in energy density of states at the Fermi level. Hydrogen in titanium aluminum alloys was found to exist in two different crystallographic environments, one diffusing faster than the other. The hydride system is probably based on the Ti2Al structure and the possible location of hydrogen in the lattice is discussed. X-ray measurements on hydrogen free Ti3Al and Ti3Al containing hydrogen giving an HTi ratio of 1.3, showed extreme distortion to the lattice upon hydrogen absorption. The X-ray diffraction lines for the hydride could not be resolved. Author
- Properties of Metals and Alloys