Quasi-periodic recalescence behaviour in undercooled eutectic alloys

A melt fluxing technique has been used to undercool Ag-Cu eutectic alloy by 10 - 70 K and the subsequent recalescence has been studied using high speed imaging. An anomalous, oscillatory growth of the solidification front was observed, in which the growth front would make a series of quasi-periodic jumps separated by extended periods during which time growth appeared to arrest. Evidence of this previously unreported mode of growth is presented. The high speed images and microstructural evidence support the theory that anomalous eutectics form by the growth and subsequent remelting of eutectic dendrites.