Theory and In Situ Diagnosis of Growth Kinetics of Dendritic Crystals in Alloy Solidification

Crystals often grow into a dendrite-like morphology after nucleation from an undercooled liquid. There are many theories about the kinetics of dendrite growth in undercooled alloys, but quantitative agreement with experiment is rare. We present a new theory that combines four types of interface kinetics with a generalized interface stability analysis for a description of dendrite growth kinetics in binary alloy solidification. The theory was tested using in situ diagnosis of dendrite tip velocity in free solidification of a Co90Cu10 alloy with the aid of a high-speed video camera. Quantitative agreement with experiment is established over a broad range of bath undercoolings, validating the four types of interface kinetics. The theory is also consistent with literature data of dendrite tip velocity-bath undercooling relationships in other alloys, indicating a universal capability of describing dendrite growth kinetics in solidification of binary alloy systems.

Automated summary

This study presents a new theory that combines four types of interface kinetics with a generalized interface stability analysis, successfully describing the kinetics of dendrite growth in binary alloy solidification. The theory is validated by quantitative agreement with experimental results and shows a universal capability in describing dendrite growth in other alloy systems.