Forming of ultrafine grained structure in aluminium by CGP method

Abstract

The severe plastic deformation method known as constrained groove pressing (CGP) was used to produce ultrafine grained (UFG) structure in recrystallized aluminium (99.99%) at room temperature. The impact of repeated groove pressing, upon microstructure refinement was investigated by transmission electron microscopy (TEM) of thin foils. The changes in mechanical properties measured by tensile and by hardness tests were related to microstructure development. The yield stress and ultimate tensile strength reached a maximum after four passes. The loss of ductility was observed in all processed plates. Hardness values measured in different area of the deformed plates indicated strain heterogeneity distribution, regardless the high straining was maintained.

Keywords

• constrained groove pressing
• aluminium
• severe plastic deformation
• microstructure evolution
• mechanical properties