TY - JOUR
T1 - Hydrogen evolution from cathodically charged two-phase (Ti3Al + TiAl) titanium aluminides
AU - Takasaki, Akito
AU - Furuya, Yoshio
AU - Ojima, Kozo
AU - Taneda, Youji
PY - 1995/7/1
Y1 - 1995/7/1
N2 - Ti-45Al and Ti-50Al (at.%) titanium aluminides, whose microstructures consisted of Ti3Al (α2) and TiAl (γ), were cathodically hydrogen-charged in a 5% H2SO4 solution for charging times up to 14.4 ks (4 h), and the dissociation process of a hydride and the hydrogen evolution process during heating were investigated by thermal analyses (differential thermal analysis and thermal desorption spectroscopy). The hydride formed during cathodic charging dissociated at the temperature of about 700 K (427 °C), and corresponding to the hydride dissociation, hydrogen gas was evolved from the alloys at the dissociation temperature. In both alloys, accelerated hydrogen evolutions were observed at the lower temperatures than that for hydride dissociation. The evolution of hydrogen in the Ti-50Al alloy was extremely accelerated at about 523 K (250 °C) and the Ti-45Al at about 600 K (323 °C). The difference in the accelerated evolution temperatures was strongly dependent on the microstructures, in which structural imperfections, such as microvoids or internal cracks, could be formed during cathodic charging. The Ti-45Al alloy picked up about 1.5-times as much hydrogen as the Ti-50Al alloy, and more than 80% of the hydrogen was concentrated at the surface layer up to 20 μm in depth from the surface of the sample.
AB - Ti-45Al and Ti-50Al (at.%) titanium aluminides, whose microstructures consisted of Ti3Al (α2) and TiAl (γ), were cathodically hydrogen-charged in a 5% H2SO4 solution for charging times up to 14.4 ks (4 h), and the dissociation process of a hydride and the hydrogen evolution process during heating were investigated by thermal analyses (differential thermal analysis and thermal desorption spectroscopy). The hydride formed during cathodic charging dissociated at the temperature of about 700 K (427 °C), and corresponding to the hydride dissociation, hydrogen gas was evolved from the alloys at the dissociation temperature. In both alloys, accelerated hydrogen evolutions were observed at the lower temperatures than that for hydride dissociation. The evolution of hydrogen in the Ti-50Al alloy was extremely accelerated at about 523 K (250 °C) and the Ti-45Al at about 600 K (323 °C). The difference in the accelerated evolution temperatures was strongly dependent on the microstructures, in which structural imperfections, such as microvoids or internal cracks, could be formed during cathodic charging. The Ti-45Al alloy picked up about 1.5-times as much hydrogen as the Ti-50Al alloy, and more than 80% of the hydrogen was concentrated at the surface layer up to 20 μm in depth from the surface of the sample.
KW - High-temperature alloys
KW - Hydrogen absorption
KW - Titanium aluminides
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U2 - 10.1016/0925-8388(95)01524-8
DO - 10.1016/0925-8388(95)01524-8
M3 - Article
AN - SCOPUS:0029346492
VL - 224
SP - 299
EP - 304
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
SN - 0925-8388
IS - 2
ER -