TWIN GROWTH IN DEEPLY UNDERCOOLED (NiFeCo)-B-Si-Nb ALLOY

Deep undercooling for Ni-base alloy, i.e., (Ni_(0.53)Fe_(0.33)Co_(0.14))_(73)B_(17)Si_8Nb_2, was obtained by technique of auto-separating denucleation of molten glass. The solidification of the undercooled Ni-base alloy is observed to be in a mode of twin growth. Mechanism on the formation and growth of twins was approached by studies of composition, structure and morphology of the alloy, together with the solidificatiion of deep undercooling alloy melt. The undercooling, crystal lattice and composition of the alloy seem to be the most important fac- tors in the formation and growth of twins.