About this Abstract |
Meeting |
Advances in Welding and Additive Manufacturing Research 2022
|
Symposium
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Advances in Welding and Additive Manufacturing Research 2022
|
Presentation Title |
Effect of Reaction Synthesis Inoculant Content on the Formation of Gas Porosity in Additively Manufactured Al 6061 |
Author(s) |
Ethan M. Sullivan, Marcia Domack, Adam Polizzi, Jeremy Iten, Jacob Nuechterlein, Stephen Liu |
On-Site Speaker (Planned) |
Ethan M. Sullivan |
Abstract Scope |
In this work, the gas porosity formation mechanism in Al 6061 metal matrix composites produced by reaction synthesis in additive manufacturing was examined with varying inoculant/reinforcement particle content. Laser-powder bed fusion and electron beam freeform fabrication additive manufacturing processes were both used. The amount of porosity was experimentally quantified via micro-computed tomography and Archimedes density measurement. The mechanism of pore formation was examined by CALPHAD/thermodynamic calculations in comparison with the experimental results. Experimental characterization revealed a larger pore size distribution in the EBF3 materials than L-PBF, with maximum bin centers of 352 µm and 53 µm for EBF3 and L-PBF, respectively. The pore size distribution in the L-PBF 2 vol.% inoculant material was observed to be statistically larger than that of the L-PBF 10 vol.% material, which is thought to be due to differences in the number of available heterogeneous nucleation sites for gas pores provided by poorly wetted secondary phase particles. Pore nucleation particles larger than the pore critical diameter was supported by pore morphology measurement via CT and density measurement results. CALPHAD and analytical thermodynamic calculations indicated different pore growth mechanisms and dominant gas phases between the EBF3 and L-PBF processes, those being buoyancy-controlled pore growth from Mg gas and diffusion-controlled pore growth from H2 gas, respectively. Mg gas porosity in EBF3 was supported by EDS measurement, which showed an average Mg concentration of 2.04 at.% in the gas pore interiors versus 1.44 at.% in the bulk Al 6061. |
Proceedings Inclusion? |
Undecided |