Crystallization kinetics of the bulk-glass-forming Pd43Ni10Cu27P20 melt

The crystallization of undercooled ${\mathrm{Pd}}_{\mathrm{43}}{\mathrm{Ni}}_{\mathrm{10}}{\mathrm{Cu}}_{\mathrm{27}}{\mathrm{P}}_{\mathrm{20}}$ melts is studied under isothermal conditions and at constant heating and cooling rates. Investigations are carried out by fluxing the melt with ${\mathrm{B}}_{\mathrm{2}}{\mathrm{O}}_3$ and without any fluxing material. The isothermal experiments allow us to determine the complete time–temperature-transformation diagram with a minimum crystallization time of about 200 s for the fluxed melt and about 130 s for the unfluxed ${\mathrm{Pd}}_{\mathrm{43}}{\mathrm{Ni}}_{\mathrm{10}}{\mathrm{Cu}}_{\mathrm{27}}{\mathrm{P}}_{\mathrm{20}}$ melt. The results of the experiments at constant cooling and heating rates are summarized in a continuous heating and cooling diagram. The critical cooling rate for the fluxed alloy is determined to be 0.09 K/s, whereas the critical heating rate is 6 K/s. For the unfluxed ${\mathrm{Pd}}_{\mathrm{43}}{\mathrm{Ni}}_{\mathrm{10\hspace{0.17em}}}{\mathrm{Cu}}_{\mathrm{27}}{\mathrm{P}}_{\mathrm{20}},$ 0.4 and 9 K/s are found, respectively. This alloy exhibits the most sluggish crystallization kinetics of all metallic systems known so far.