Mechanical behavior of additively manufactured AlSi10Mg alloy with annealing state under extreme conditions

In this paper, AlSi10Mg alloy was prepared by selective laser melting (SLM) first, and then subjected to stress relieved annealing treatment. The microstructures of the alloy were analyzed by optical microscope (OM), scanning electron microscope (SEM) and electron backscatter diffraction (EBSD) technology; the mechanical behavior of the alloy under extreme conditions (high and low temperatures, high strain rate) were analyzed by universal testing machine with an environmental chamber and split Hopkinson pressure bar. The results show that AlSi10Mg alloy possesses fine cellular dendritic microstructure, mainly including α- Al and Si phases, and annealing treatment can result in the discontinuous distribution of eutectic Si particles. AlSi10Mg alloy shows strain rate strengthening effect under room temperature condition at 0.002s-1 ~4800 s-1, and has different strain rate sensitivity in different strain rate ranges; flow stress is not sensitive to temperature at 173 K~243 K, but it becomes sensitive when the temperature at 293 K~573 K, and the softening effect increases with the increase of temperature. Based on the experimental results, the modified J-C constitutive model was fitted and validated, which can well reflect the mechanical behavior of the material at high and low temperatures and different strain rates.