4:10 PM - 4:30 PM
[16A-T7-26] Debinding, a Key Stage in the Manufacture of Inconel 718 Parts by MBJ
Keywords:Metal Binder Jetting, Debinding, Sintering, Inconel 718
Metal Binder Jetting (MBJ) is an indirect additive manufacturing technique without melting. It consists of selectively spraying a polymeric binder onto a powder bed, layer by layer. The green part is then obtained after curing and depowdering. A debinding step ensures the removing of polymer residues before a final stepwise sintering improves the mechanical properties. Poor debinding control leads to carbon contamination, causing carbide precipitation during sintering and impacting the microstructure.
Comparing sintered MBJ and compacted powder parts reveals differences. While the latter exhibits a typical IN718 microstructure, carbides precipitation and limited amount of γ'' and γ' phases lead to an MBJ part half as hard. An oxidizing atmosphere is therefore recommended for debinding, although it hinders densification during sintering due to the powder oxidation. Thermogravimetric experiments combined with SEM observations have provided a better understanding of the thermal and thermochemical degradation of the polymer to achieve optimal sintering.
Comparing sintered MBJ and compacted powder parts reveals differences. While the latter exhibits a typical IN718 microstructure, carbides precipitation and limited amount of γ'' and γ' phases lead to an MBJ part half as hard. An oxidizing atmosphere is therefore recommended for debinding, although it hinders densification during sintering due to the powder oxidation. Thermogravimetric experiments combined with SEM observations have provided a better understanding of the thermal and thermochemical degradation of the polymer to achieve optimal sintering.