The effect of foreign particles on the interface shape during solidification of crystals

AGALIOTIS ELIANA M.; ROSENBERGER MARIO R.; ARES ALICIA E.; SCHVEZOV CARLOS E.

Madrid

Congreso; XXII Congress and General Assembly of the international unión of crystallography; 2011

International Union of Crystallography

The shape of a solidifying interface is generally affected when it encounters foreign inert particles. The degree of deformation depends on the morphology and physical properties of the particles [1-4]. The overall effect also affects the pushing and captures process, when pushing is present. In the present report the interaction between particle and interface is analyzed by means of a mathematical model employing the finite element method. The effect on the interface of different particle shapes and relative thermal conductivities between particle and melt was studied. The results sown that for an isolating particle with respect to the melt the interface is convex in a degree that changes depending on the particle shape and separation distance from the interface. The particle geometries considered for simplicity were spherical, cylindrical, conical and semi-spherical. For a conducting particle the interface changes to concave. From the observation of the present results the trapping of the particles by the solid starts in different places; for a conducting particle the first points touching the solids are the corners while for an isolating particle this occurs at the particles center. The analyses of these observations indicate that the probability of pore formation could be higher when isolating particle are present in the melt.   [1] A. A. Chernov and D. E. Temkin, D. E., 1976 Crystal Growth and Materials, North Holland, Amsterdam 1977, 3-77. [2] J. K. Kim  and P. K. Rohatgi, Acta mater. 1998, 46(4), 1115-l123. [3] A. V. Catalina, S. Mukherjee, D. Stefanescu, Metallurgical and Materials Transactions A31, 2000, 2559-2568. [4] J. W. Garvin, Y. Yang, and H.S. Udaykumar, International Journal of Heat and Mass Transfer, 2007, 50, 2969-2980.