Rabochiy P. Hydrodynamical effects accompanying the directional solidification of the binary melts

The thesis deals with modeling of processes in a liquid phase of the substance accompanying the directional solidification of the binary melts. Numerical modeling of influence of vibration on convective processes in melt and the distribution of a dopant in a crystal is carried out for microgravity conditions. It is shown that vibrating influence can result in occurrence of periodic spatial concentration inhomogeneity in a crystal. The technique, which allows to improve the refinement of substance due to additional impulsive heating of the melt, is offered. The problem of influence of a translational vibration along the direction of crystal growth on the stability of a solid-liquid interface is considered for microgravity conditions. It is shown that vibration leads to the same effect as the gravity in terrestrial conditions, resulting in occurrence of the long-wave instability (vibrational mode) caused by hydrodynamical effects in the melt. The increase in the velocity of crystal growth stabilizes vibrational instability and destabilizes morphological instability. As a result, stability of crystallization front is possible only in a narrow interval of growth velocity values between the maximal critical velocity for a vibrational instability and the minimal critical velocity for a morphological instability.