Apparatus for mixing particles into a liquid medium

An apparatus for mixing ceramic particles into a liquid or semi-liquid medium to form metal matrix composite material, the apparatus comprising:

• a vessel having a side wall and a bottom wall and defining a medium receiving chamber, the medium receiving chamber adapted to contain a metal matrix therein;
• a rotatable impeller comprising an impeller tube mounted for rotation relative to the vessel, the impeller tube having an inner passage and an impeller head, wherein the impeller head is disposed in the chamber and wherein the impeller head has a non-planar inner contour, the inner contour of the impeller head at a non-orthogonal angle relative to the longitudinal axis of the impeller tube;
• an impeller base coupled to and projecting upward from the bottom wall of the vessel such that the impeller base is above the bottom wall, the impeller base proximate to the impeller head, the impeller base having an outer contour facing the inner contour of the impeller head, the outer contour of the impeller base complementary in shape and substantially parallel to the inner contour of the impeller head so as to define a shear region in the metal matrix between the impeller head and the impeller base when the impeller is rotated;
• and
• solids pump means coupled to the inner passage for feeding the ceramic particles into the metal matrix within the chamber such that the metal matrix composite material is formed;
• whereby the ceramic particles are directed through the inner passage and into the metal matrix through the shear region such that the ceramic particles are immediately sheared into the metal matrix at a point of maximum shear force.