Abstract
During rapid solidification, nonequilibrium interface kinetics alter the predictions of the Mullins-Sekerka theory for the stability of a planar interface against cellular breakdown. The velocity-dependence of the partition coefficient and of the Sn concentration at the onset of cellular breakdown have been measured during pulsed laser melting of Si-Sn alloys. The Mullins-Sekerka theory is modified by inserting a velocity-dependent partition coefficient and a velocity-dependent slope of the "kinetic liquids", both of which are extracted from the continuous growth model for interface kinetics. These nonequilibrium interface kinetic effects increase the predicted critical concentration for cellular breakdown by two orders of magnitude for Sn in Si, and account fairly well for the experimental results.
| Original language | English |
|---|---|
| Pages (from-to) | 107-112 |
| Number of pages | 6 |
| Journal | Journal of Crystal Growth |
| Volume | 109 |
| Issue number | 1-4 |
| DOIs | |
| State | Published - Feb 2 1991 |
| Externally published | Yes |
Funding
We are grateful to C. Hayzelden for instruction in Z-contrast imaging, to R.E. Blake for technical assistance with pulsed laser melting, and to S.R. Coriell for assistance with the numerical solution to the stability equations. Samples were implanted at the Surface Modification and Characterization Facility at Oak Ridge National Laboratory. Work at Harvard was supported initially by the Harvard MRL through NSF-DMR-86-14003 and by a grant from Sandia Laboratories, and subsequently by the DOE through DE-FGO2-89ER45401 (J.B. Darby). Work at Cornell was supported by NSF-PYIA (J. Hurt). Work at Sandia was supported by the DOE through DE-ACO4-76DP00789.