Tuning the microstructure and mechanical properties of AlSi10Mg alloy via in-situ heat-treatments in laser powder bed fusion
Federico Bosio, Chinmay Phutela, Natalia Ghisi, Alya Alhammadi, Nesma T. Aboulkhair
Abstract
Together, advanced technologies and metallic materials rapidly progress in the field of Laser Powder Bed Fusion (PBF-LB) additive manufacturing (AM). Although PBF-LB drastically shortens the design-to-manufacture time, post-processing operations on metal parts, including heat-treatments, are often labour intensive and time-consuming. Therefore, we assess the feasibility of conductingin-situ heat-treatments during PBF-LB of AlSi10Mg parts. A build plate heated at set temperatures up to 500 °C was employed while printing for 10–13 h to tune the material's microstructure. For comparison, a batch of samples was printed at 220 °C and 500 °C with a printing time of 4–6 h, which was subsequently solution heat-treated. The experimental results showed that increasing the printing time from 5 h to 11 h while printing at 220 °C resulted in an in-situ direct aging heat-treatment with an actual increment of hardness and strength. Printing at 300 °C induced a significant Al lattice relaxation and consequent in-situ stress relieving of the as-built parts. Lastly, the study shows that in-situsolution heat-treatment is possible when using build plate temperatures between 450 °C and 500 °C for 11 h, although a reduction in ductility (−36%) occurs, as compared to conventionally solution heat-treated counterparts.