CORRESPONDENCE BETWEEN STRAIN AND GRAIN BOUNDARY EVOLUTION IN PURE ALUMINIUM DURING HIGH PRESSURE TORSION TO LARGE STRAINS

In this report, evolution of grain boundary structure in a 99.99% purity Al during high pressure torsion (HPT) is investigated using high-resolution electron backscatter diffraction analysis. It is found that evolution of the deformation-induced boundaries is in a fairly good correspondence with hypothesized simple-shear mode of deformation during HPT. However, the correspondence is lost at equivalent strain level of similar to 8 when the grain refinement saturates. Comparison of the 4N-Al structure evolution deformed by different methods further confirms correctness of our approach to calculate equivalent values during HPT.