Abstract

A new method and apparatus for the injection molding of semi-solid materials (SSM). In this process (called Rheomolding), a superheated liquid metal is cooled into the semi-solid state in the barrel of a special vertical injection-molding machine, with the growing dendrites of the solid phase being broken into small and nearly spherical particles by the shearing force generated by the screw and barrel. Compared with the superheated liquid metal, SSM has lower temperature, lower shrinkage and a more stable flow pattern. Therefore, the rheomolding process can produce net-shape metal or metal-matrix-composite parts continuously at lower cost.