Investigation of dehydrogenation of Ti-V-Cr alloy by using in-situ neutron diffraction

摘要

The hydride phase of Ti50V20Cr30 alloy cast with 4 wt% of 7Zr+10Ni has been investigated. Pressure composition desorption isotherms were measured at 150 degrees C and 200 degrees C. These isotherms revealed same desorption of 1.5 wt% at 150 degrees C and 200 degrees C. The evolution of the crystal structure upon dehydrogenation was investigated by in-situ neutron diffraction. A sample was fully deuterated at room temperature under 2000 kPa pressure. Afterwards, the sample was heated from 120 degrees C to 266 degrees C under vacuum and neutron diffraction patterns were recorded as a function of temperature. It was found that the alloy started to desorb very quickly at 200 degrees C. The amount of fcc phase was monitored using the relative intensity of the fcc phase compared to a standard. At 266 degrees C only 10% hydride phase was seen, which was confirmed by X-ray diffraction. Besides the fcc phase, a minor aluminum phase due to the heating element was also observed in all patterns. Thermal expansion coefficient of Al and fcc phase were calculated. Using the aluminum peaks as reference, it was found that deuterium occupancy reflect the phase abundance of the fcc deuteride. (c) 2020 Elsevier B.V. All rights reserved.