Convective and morphological instabilities during crystal growth: Effect of gravity modulationDuring directional solidification of a binary alloy at constant velocity in the vertical direction, morphological and convective instabilities may occur due to the temperature and solute gradients associated with the solidification process. The effect of time-periodic modulation (vibration) is studied by considering a vertical gravitational acceleration which is sinusoidal in time. The conditions for the onset of solutal convection are calculated numerically, employing two distinct computational procedures based on Floquet theory. In general, a stable state can be destabilized by modulation and an unstable state can be stabilized. In the limit of high frequency modulation, the method of averaging and multiple-scale asymptotic analysis can be used to simplify the calculations.
Document ID
19950051022
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Coreill, S. R. (U.S. Dept. of Commerce, Gaithersburg, MD US, United States)
Murray, B. T. (U.S. Dept. of Commerce, Gaithersburg, MD US, United States)
Mcfadden, G. B. (U.S. Dept. of Commerce, Gaithersburg, MD US, United States)
Wheeler, A. A. (U.S. Dept. of Commerce, Gaithersburg, MD US, United States)
Saunders, B. V. (U.S. Dept. of Commerce, Gaithersburg, MD US, United States)