Local stress and strain in heterogeneously deformed aluminum: a comparison analysis by microhardness, electron microscopy and finite element modelling

The local stress and strain are analysed in a heterogeneous microstructure induced by compression of aluminium rings under nearly full sticking conditions. This analysis is based on characterization of mechanical behaviour and microstructure applying three complementary techniques covering multiple length scales: microhardness, electron microscopy (electron backscatter diffraction) and finite element modelling. The findings are underpinned by applying those techniques in an analysis of a homogeneous microstructure induced by compression of hot-extruded aluminium cylinders. The local stress and strain are estimated at 14 different positions in two rings representing large variations in strain. A comparison with the stress and strain in the homogeneously compressed cylinders related to the average spacing between deformation induced low and high angle boundaries, validates the characterization techniques and supports a hypothesis that the microstructure of local regions in a heterogeneous structure evolve in accordance with universal principles and mechanisms established for the evolution of the deformation microstructure of polycrystalline metals.