Abrupt change in heat capacity of supercooled Pd-Cu-Ni-P melt during continuous cooling

Recently, it has been reported that the new quaternary Pd₄₀Cu₃₀Ni₁₀P₂₀ alloy has a high resistibility against crystallization in an undercooled liquid state and exhibits an outstanding high glass-forming ability. We investigated the glass-transition behavior of the alloy under continuous cooling condition, and succeeded in detecting an abrupt change in C_p. At a cooling rate of 1.67 K/s, the onset glass-transition temperature was detected at 585 K and the difference of heat capacity (ΔC_p) between the supercooled melt and the glass was 9.07 J/mol K at a half point of transition. On the other hand, the heat release due to the crystallization was detected at a cooling rate of 0.33 K/s, and no abrupt change in C_p was detected. The thermodynamic parameters determined in the present study enables us to interpret the reason for the outstandingly high glass-forming ability of the alloy.