Peri‐eutectic transition during crystallization of undercooled ternary alloy melt

Peri‐eutectic transition was investigated in terms of the dependence of crystallization behavior on undercooling in Cu–Ag–Ge ternary alloy composed of (Ag), ζ(Cu 5 Ge), and ε 2 (Cu 3 Ge) phases. (Ag + ε 2 ) pseudobinary eutectic is the product of both peri‐eutectic and subsequent pseudobinary eutectic transitions. Nanoscale structure of anomalous (Ag + ε 2 ) pseudobinary eutectic forms at the maximum undercooling, which is ascribed to the independent nucleation and growth from the liquid. The decrease of (Ag + ε 2 ) pseudobinary eutectic at a high undercooling is due to that the phase transition happening at the beginning solidification stage proceeds more thoroughly at a higher undercooling.