Dehtyarenko V. Hydrogen interaction with eutectic alloys of the Ti-Zr-Mn and Ti-Fe-Mn alloy system.

The location in the Ti-Zr-Mn system of the coexistence curve for eutectic reaction for the partial Тi-ТiMn2-ZrMn2-Zr system was defined more accurately. In the Ti-Fe-Mn system the polythermal TiMn2-TiFe2 section, which can be attributed to the cigar type of the diagram of melting, was constructed. It was shown that hydrogenation process of eutectic alloys in the Ti-Zr-Mn system takes place in two stages. First stage passes at approximately constant rate; the second, final stage takes place with the 10 times faster rate. The presence of the primary crystals of the (Ti,Zr,Mn) solid solution in alloy does not change the manner of passing for absorption but increases the time of hydrogenation. The presence of the primary crystals of the (Ti,Zr)Mn2-x intermetallic compound decreases not only the incubation period but the duration of the hydrogen absorption process to few minutes. The composition of (Ti,Zr)Mn2-х intermetallic compound, which is able to sorb hydrogen at room temperature during few minutes up to Н/Ме=1,5 capacity without preliminary activation, was determined for the very first time; phase composition and crystal structure of the products of hydrogenation and desorption were determined as well. It was found that hydrogen absorption at room temperature and hydrogen pressure of 0.6 MPa during 50 hours does not take place for eutectic alloys of Ti-Fe-Mn system. Absorption start was observed at the same hydrogen pressure and heating to 500°С with 3°С/min heating rate. It was shown that the process of hydrogenation of the (Ti,Fe,Mn)+ro-TiMn +TiFe eutectic in Ti-Fe-Mn takes place in two stages. First stage passes at approximately constant rate; the second, final stage takes place with the 10 times faster rate. The presence in alloy of the non-equilibrium remaining primary crystals of the Ti(Fe,Mn)2-x intermetallic compound leads to shortening of the first stage of hydrogenation; the rate of hydrogenation exceeds by 4 times corresponding rate for eutectic alloy at that.