Hydrogenation and microstructural study of melt-spun Ti0.8V0.2

In this work we utilized the melt spinning process to prepare a nanostructured Ti0.8V0.2 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 Ti0.8V0.2 and rapidly solidified (RS) materials (RS1000 and RS3000) formed FCC dihydrides with lattice parameters ranging from 4.4198 to 4.4338 Å. RS resulted in a dramatic decrease of the grain size, down to smaller than 200 nm for the hydrogenated Ti0.8V0.2 RS3000 alloy. The thermal stability of the hydrides was strongly affected by the RS solidification rate. For the hydride of Ti0.8V0.2 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.

Research highlights▶ Ti0.8V0.2 hydrogen storage alloy has been produced using melt spinning technique. ▶ Hydrogenated Ti0.8V0.2 ribbon which was prepared using 3000 rpm spinner velocity had grain size of 200 nm due to grain refinement during rapid solidification. ▶ Decreased thermal stability of the hydrides was observed as a result of the rapid solidification process, the TDS peak temperature was shifted by ∼80 centigrades compared to that of the as cast hydrogenated alloys.