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Semi-solid processing (SSM) has many advantages in that the alloy is cast at lower temperatures (i.e., in the two-phase region) giving rise to reduced die wear, as well as giving rise to novel microstructures. The resultant SSM processed castings are dendrite-free and do not contain hot tears; rather, the SSM structure is globular, and the liquid phase surrounding the globules acts as a “lubricant” during processing. Moreover, the flow of the slurry into the die cavity is more laminar than turbulent, since the starting metal is in the mushy region. This concept of SSM processing was realized by the development of a continuous process titled: CRP - Continuous Rheo-conversion Process. In this process, one allows the incipient solidification of alloy melt(s) under the combined effects of forced convection and rapid cooling rates. In the CRP, two liquids held at particular level of superheat, are passively mixed within a reactor.

Squeeze casting is considered a “high integrity” casting process because it imparts qualities (higher tensile properties, in particular ductility due to reduced or absence of porosity in the matrix, and the ability to heat treat) to a metal that are difficult to achieve with conventional casting techniques including gravity permanent mold (GPM) and high pressure, high velocity (HPDC) die casting. In recent years, the squeeze casting process has been widely used with various aluminum alloys to manufacture near-net shape automotive components requiring high strength, ductility or pressure tightness. However, with the emphasis on weight reduction, lower cost and improved performance of structural components, alternative lightweight materials including magnesium are now being seriously considered. Unfortunately, the use of magnesium as a structural material has been hindered by the lack of data on mechanical properties and the lack of new improved casting methods.