Development of a Versatile Rheocasting Technology

Since 2003, a concerted effort between Alcan Inc. (ARDC: Arvida Research and Development Centre) and the Aluminium Technology Centre (ATC) of the National Research Council of Canada is underway to develop a technology, dubbed SEED (Swirled Enthalpy Equilibration Device), to produce semi-solid aluminium feedstock. This technology, patented by Alcan Inc., is a simple process offering many advantages over thixocasting, especially for reducing the cost of feedstock. The process involves two main steps: 1) heat extraction to achieve a desired liquid/solid mixture, and 2) drainage of an excess liquid to produce a self-supporting semi-solid slug that is cast in a high pressure press. This paper reports that the SEED technology is applicable to a number of aluminium alloys and can be easily adapted to produce a wide range of slug dimensions. Furthermore, since the heat transfer plays a predominant role during the manufacture of the semi-solid slurry, its analysis is also presented.