Melt refinement treatment（or external field treatment）is one of the important categories of metal-melt treatment technology.It is applied for semi solid or liquidus rheoforming to achieve entire homogenization and refinement of the casting structure.Based on cost and performance

three principles for evaluation of the external field technologies were presented as follows:simple process

uniform refinement and low defect.Through objective evaluation of the existing external field technologies

a novel rotary shearing dispersing technology（RSD）which similar to soymilk-maker is feasible in generous commercial applications.