Order hardening of Pt8X alloys

Platinum containing around 11.1 at.% chromium or vanadium undergoes an ordering transformation upon heat treatment, resulting in the formation of ordered domains with the Pt8Ti superlattice structure. The formation of these ordered domains, which are dispersed in a disordered matrix, results in an increase in hardness. Hardness is observed to be sensitive to domain size, with a maximum hardness at around 5 nm, if the ordered volume fraction is high.