Developing novel heterogenous microstructures to balance between strength and ductility without restoration processes in commercial Al alloys

Abstract

The mechanical response of polycrystalline materials significantly depends on the details of the microstructure. For example, different spatial grain size distributions can lead to different mechanical response. Deformation produces a hardened material and a loss of ductility, while annealing makes the metal softer as a direct result of the loss of dislocations via recovery and recrystallization. However, introducing a limited fraction of heterogeneity into the microstructures can be useful in balancing the typical tradeoff between strength and ductility even without the need to perform a subsequent restoration process (recrystallization). The objective of this work is to devise computational microstructural evolution tools to design heterogeneous microstructures comprised of rolled and equiaxed structures simultaneously. Afterward, these heterogeneous structures are experimentally produced in commercial purity Al by a simple rolling process on a complex sample geometry and mechanically tested (tension test). Electron backscatter diffraction (EBSD) measurements are made to validate the computer simulation results.