“…PBF studies have shown that both compound grain refiners such as TiB, TiC and TiN [13][14][15] and single phase/element grain refiners, like most peritectic elements and Sc, provide excellent grain refinement [4,16,17,18,19,20,21]. It is, however, far from clear that the nucleation sequence occurring during casting, also occurs during PBF, as both the solidification rate (10 6 -10 7 K°/s) and melt temperature (reaching boiling point of the metal) are several orders higher [22].…”