Hydrogen corrosion and mobility in T225 titanium alloy by ion beam and material analysis methods


Hydrogen corrosion and mobility in T225 titanium alloy by ion beam and material analysis methods

Wang, T.; Grambole, D.; Grötzschel, R.; Herrman, F.; Kreissig, U.; Eichhorn, F.; Brauer, G.; Möller, W.

The behaviour of hydrogen implanted into Ti225 alloy is studied in this work. The hydrogen depth profiles vs. different implantation doses and ion energies were measured with resonant Nuclear Reaction Analysis (NRA) and Elastic Recoil Detection Analysis (ERDA). The hydrogen diffusion to the surface at room temperature is found from the depth profiles which differ from their theoretical simulation due to a more complex diffusion and hydrogenation than described at present by theory. A rapid formation of titanium hydrides, i.e. TiH1 and TiH2 , is found in the implantation dose range between 6x1016 and 2x1017 H1/cm2 by X-ray diffraction. The phase transformation from TiH1 to TiH2 crystal structure starts after implantation of 1x1017 H1/cm2, and is finished at a dose of 6x1017H1/cm2 at which a saturation of the hydrogen concentration of about 23 at.% is found from the depth profiles. The titanium hydrides are inhomogeneously distributed in the sample. The hydrogen contour maps measured by the scan of micro-beam ERDA show dose-dependent inhomogeneities due to the hydride formation process. The radiation damage affects also the hydrogen concentration and out-diffusion. A defect-related trapping of hydrogen is observed by slow positron implantation spectroscopy (SPIS). The surface hydride layer on titanium acts as a highly effective barrier to oxygen. It is found that the oxidation ratio is strongly reduced already by implantation of only 2x1016 H1/cm2.

Keywords: Titanium; Hydrogen implantation; Titanium hydrogenation; Ion beam analysis; X-ray diffraction

  • Lecture (Conference)
    International conference on Surface Modification of Materials by Ion Beam, (SMMIB 2001), Marburg, Germany, Sept. 7-13, 2001

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Publ.-Id: 4763