The mechanical behavior and microstructure of additively manufactured AlSi10Mg for different material states and loading conditions

The mechanical behavior of AlSi10Mg produced by selective laser melting (SLM) and heat treated to T5 and T6 was investigated under uniaxial compressive, tensile and combined shear-compression loading for strain rates up to 2·10³s⁻¹ and different temperatures (23 °C/400 °C). AlSi10Mg-T5 possess lower strength but higher elongation to fracture, higher specific absorbed mechanical energy and higher strain rate sensitivity as the T6 condition. In addition, the material in the T6 state was found to be more prone to biaxial loading and elevated temperature than the T5 state. The microstructural and fractographical investigation reveal that these differences are mainly related to different sizes and species of precipitates. The study is complemented by a constitutive description of the flow stress as function of strain and strain rate for the whole range of strain rates. This model is based on the Orowan equation including dislocation drag mechanism in combination with the well-known Kocks-Meckin-Esrin approach. With this modelling it was shown that typical length scales, mobile/total dislocation densities and dislocation generation/annihilation significantly differ as function of strain.