Hardness, microstructure and strain distributions in commercial purity aluminum processed by multi directional forging (MDF)

Abstract

Severe plastic deformation (SPD) of metals leads to their strengthening and grain refinement, but to low uniform elongations. Low Strain Amplitude Multi Directional Forging (LSA-MDF) is an important method for increasing this low uniform elongation. The application of workpieces of SPD-processed materials requires that their distributions of mechanical properties, microstructures and deformation be as homogeneous as possible. Analyses of these distributions after LSA-MDF have not been found in the literature, and are presented in the current investigation utilizing microhardness measurements, optical and electronic microscopy and finite element simulations. LSA-MDF causes higher strains, mcrohardeness and structural distortions in the central regions of the specimens than at their edges and corners. In addition, LSA-MDF utilizing confined compressions seems to be the preferred processing route, due to its ease and to the more homogeneous microhardness, microstructure and strain distributions in relation to other experimental procedures.