Effect of low-frequency vibration on nucleation of crystals in supercooled melts

Nucleation of transparent organic substances in supercooled melts under vibration (50 Hz, 1–5 mm) has been studied experimentally. In the absence of a seeding crystal, vibration did not affect nucleation within the whole range of melt supercoolings studied, ΔT= 0.1–10 K. The introduction of a seeding crystal provides a threshold supercooling ΔT* below which no nucleation occurs at all, whereas above it, an explosion-like nucleation is observed. It is shown that mass growth of small crystals at ΔT>ΔT ^* is not associated with the detachment of growing-crystal fragments and seems to be explained by three-dimensional nucleation on the surface of a seeding crystal.