Zn did also not diffuse into steel matrix. The reacted 55wt.% Al–Zn coating
on the PHS did not make the steel susceptible to LME, despite the
fact that liquid Zn was present during the press forming. This is due to
the fact that the liquid Zn was fully confined to the reacted 55 wt.%
Al–Zn layer as intergranular islands or at grain boundaries between
Fe–Al intermetallic grains. This local confinement of the Zn prevented
all reactions between the Zn and the steel matrix, thereby suppressing
LME.