|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Additive Manufacturing of Large-scale Metallic Components
||The Effects of CoAl2O4 on the Microstructural Evolution of Inconel 718 Processed by Direct Energy Deposition
||Dhruv Tiparti, I-ting Ho, Tilo Buergel, Fred Carter, Sammy Tin
|On-Site Speaker (Planned)
Processing of Inconel 718(IN718) mixed with CoAl2O4 grain refiners via direct energy deposition (DED) has revealed some unintended microstructural modification effects. The physical presence of these oxides within the melt pool suggests a decrease in convective heat transfer due to increased fluid viscosity induced by a nano/micro particle slag. This decrease in convective flow is accompanied by increased melt pool penetration depth which has consequences of earlier onset of large columnar grains extending across multiple layers. Due to the low and heterogeneous distribution of strain energy within DED processed material; recrystallization kinetics are hindered by a potent Zenner pinning effect that leads to retention of the as-built microstructure even following aggressive heat treatment of 1200 oC up to 4 Hrs. The minor addition of oxide particles shows potential avenues for increased microstructural control of additive materials. Further detail of the results and accompanying discussion will be presented.
||Additive Manufacturing, High-Temperature Materials, Characterization