Principle of the Continuous Variable Cross-Section Recycled Extrusion (CVCE) Process

A kind of severe deformation method for refined grain materials named continuous variable cross-section recycled extrusion (CVCE) was proposed. The composition structure and working principle of processing were introduced. First, the cylinder specimen was extruded to circular cone and then the circular cone specimen was compressed into columned one. After that, the specimen was rotated by 180° and repeated the forward procedure. All of procedures mentioned above constitute a cycle. The whole process is repeated again and again. The process can introduce ultra-high plastic strain without any geometrical change. The process has been applied to commercial aluminum (1100), Mg alloy. After several cycles of CVCE, bulk materials with sub-micron grain structure were successfully obtained. The average grain size of AZ31 magnesium alloy is refined from 25μm to 3μm after six cycles and the tensile elongation were improved dramatically.