Microstructure and activation and hydrogenation properties of Zr₅₇V₃₆Fe₇ alloy

The microstructure and phase structure of Zr₅₇V₃₆Fe₇ alloy were investigated. Activation property of the Zr₅₇V₃₆Fe₇ alloy was tested. Hydrogen absorption pressure composition temperature (P-C-T) property was investigated by a pressure reduction method at the temperatures ranging from 673 to 823 K. The results indicate that the microstructures of the alloy before hydrogen absorption are constituted of lath-shaped solid-solution grains and irregular lamellar eutectic structures. The dominant hydriding phases are ZrV₂ phase and α-Zr phase. After hydrogen absorption the dominant phases are ZrH_1.801 phase and V₁₆Zr₈H_36.29 phase. The alloy can be fully activated by heating at 723 K for 1 h in vacuum followed by a hydrogen absorption and desorption cycle. P-C-T curve exhibits a wide and flat platform. The thermodynamic parameters of the reaction can be calculated using Van't Hoff equation. The equilibrium hydrogen pressure can reach the level of 10^-8 Pa at room temperature.