Hi, in Aluminium alloy, V2O5 located at grain boundary and prevents from grain growth. vanadium, titanium, niobium and their alloys are very effective in the grain refinement in Aluminium alloys. good luck, yours sincerely.

These oxide particles are present in all over the matrix but maximum of them are present in grain boundaries. Because of their existence in grain boundary region the grain growth will restricted due to which grain refinement takes place. Ultimately, grain refinement increases the strength of the material but somehow decreases the corrosion resistance. You can refer my papers.

Small Vanadium Oxide particles play a role of substrates for heterogeneous nucleation throughout solidification of Aluminum. That causes a grain refinement of the alloy's microstructure.