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Die Akkumulation von Defekten in Titan, nach elektrolytischer Wasserstoffsättigung

: Chernov, I.; Cherdantzev, Y.; Lider, A.; Garanin, G.; Kröning, M.; Baumbach, H.

WOM 2001 Wodorodnaja Obrabotka Materialow. Bearbeitung von Materialien mit Wasserstoff. Bd.2
Donetzk-Mariupol, 2001
Internationale Konferenz "Bearbeitung von Materialien mit Wasserstoff" <3, 2001, Donetzk-Mariupol>
Conference Paper
Fraunhofer IZFP ()
Titan; defect; Wasserstoffsättigung

The hydrogen influence on dynamics of defects formation in VT1-0 titanium was studied. Studying surface of titanium used as cathodes at an electrolytic hydrogen charge from LiOh+H2O solution was performed by optical and raster electronic microscopes. The method of a positrons annihilation was used for studying concentration and types of defects in a bulk of metal. After a mechanical and electrochemical polish, samples of the 50x5x1 mm dimensions was exposed by vacuum annealing during 120 min at temperature 700°C with following slow cooling. The electrolytic charge by hydrogen in LiOh+H2O solution were performed at a current density 0,5-1 A/cm2 (platinum was used as anode). The enriching of a titanium bulk by hydrogen (for sample by 1000 mm depth) up to maximum concentration is achieved for 4 hours for these conditions, as shown. Optical and raster electron microscopy, have revealed a considerable amount of the defects on a sample surface which have appeared after enrichment with hydrogen. Already after 2 or 3 minutes of an electrolysis at a current density 1 A/cm2 on a metal surface there are dotted formations up to 1mm in diameter. It is connected with nonuniform evolving of a hydrogen phase of titanium, which grows from a surface to depth of metal. A metal surface is coated fully with similar formations after 20-minutes enriching. Craters (up tp 10 mm in diameter) and cracks found on a samples surface after 120 minutes of a hydrogen enriching. The studying of titanium bulk defects were performed by positrons annihilation method. The results of measurement of a positrons lifetime have shown, that about 150 microns depth the fundamental contribution (up to 90%) is determined by single vacancies and dislocations.