Tuning the defects density in additively manufactured fcc aluminium alloy via modifying the cellular structure and post-processing deformation

Abstract

In this study, using an L-PBF AlSi10Mg alloy with different microstructural properties, the typical structural defects caused by severe plastic deformation are investigated by scanning electron microscopy and high-resolution transmission electron microscopy. Microscopic characterization shows that the deformed L-PBF AlSi10Mg alloy exhibits a heterogeneous microstructure consisting of Al/Si interfaces and a high density of dislocations, stacking faults, and nanotwins. On the basis of experimental data, it is also shown that high stresses build up at the Al/Si interface due to incompatible deformation, enabling the activation of novel deformation modes that control the plastic deformation of the hard Si twin phase and amorphization in the solid state. The revealed synergy and novel deformation modes open a new horizon for the development of next-generation structural materials and provide insights into the atomically resolved structures of dislocations and GBs in nanostructured L-PBF alloys.