Helium bubble formation in additive manufactured L-PBF AlSi10Mg

Laser powder bed fusion additive manufacturing shows great promise for the nuclear industry due to unique and novel metallurgical phenomena and superior properties compared to cast or wrought products. The correlation between the unique microstructure of additively manufactured AlSi10Mg alloy, the radiation damage accumulation and its effect on the mechanical properties is examined. Laser powder bed fusion AlSi10Mg alloy was subjected to He⁺ ions implantation over an energy range that produced a 2 μm uniform layer within the bulk material to yield a local dose of 2000 appm at the depth of the material. It is shown that for each microstructural component the Helium bubble size, distribution and density depends on its stopping range. Furthermore, the overall increase in nanohardness in the irradiated region is in correlation with the measured defect density. In this unique microstructure interfaces play a diminished role at accumulating Helium bubbles compared to dislocations and dislocation structures indicating their relative sink strength.