Hydrogenation and microstructural study of melt-spun Ti_0.8V _0.2

In this work we utilized the melt spinning process to prepare a nanostructured Ti_0.8V_0.2 alloy for hydrogen storage applications. The alloy ribbons were solidified from the melt using two different wheel spinner velocities, 1000 and 3000 rpm. LOM, and SEM were utilized to examine the microstructures of the ribbons and their corresponding hydrides. Hydrogen absorption and desorption experiments were performed using a TDS setup. Arc melted Ti_0.8V_0.2 and rapidly solidified (RS) materials (RS1000 and RS3000) formed FCC dihydrides with lattice parameters ranging from 4.4198 to 4.4338 . RS resulted in a dramatic decrease of the grain size, down to smaller than 200 nm for the hydrogenated Ti_0.8V _0.2 RS3000 alloy. The thermal stability of the hydrides was strongly affected by the RS solidification rate. For the hydride of Ti _0.8V_0.2 RS3000, a significant decrease in the thermal stability was observed, so the peak of hydrogen desorption was shifted to much lower temperatures, by ∼80 °C, as compared to the hydrogenated as cast alloy.