TY - JOUR
T1 - Mechanical properties of hybrid additively manufactured Inconel 718 parts created via thermal control after secondary treatment processes
AU - Glerum, Jennifer
AU - Bennett, Jennifer
AU - Ehmann, Kornel
AU - Cao, Jian
N1 - Funding Information:
This research received funding from the US Army Research Laboratory (award W911NF-19-2-0092 ). JAG and JB were supported by the Army Research Laboratory (ARL) Oak Ridge Associated Universities (ORAU) via a Journeyman Fellowship grant. This work made use of the EPIC facility of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource ( NSF ECCS-1542205 ); the MRSEC program ( NSF DMR-1720139 ) at the Materials Research Center ; the International Institute for Nanotechnology (IIN) ; the Keck Foundation ; and the State of Illinois , through the IIN. This work also made use of the Center for Hierarchical Materials and Design (CHiMaD under grant No. 70NANB14H012 ) Metals Processing Facility, and the MatCI Facility which receives support from the MRSEC Program ( NSF DMR-1720139 ) of the Materials Research Center at Northwestern University. The authors acknowledge Suman Bhandari (NU) for assistance with the Bruker Alicona notch measurement and thank Prof. David Dunand (NU), Prof. Gregory Wagner (NU), and Dr. Jon-Erik Mogonye (U.S. Army Research Laboratory, Adelphi) for numerous useful discussions.
Funding Information:
This research received funding from the US Army Research Laboratory (award W911NF-19-2-0092). JAG and JB were supported by the Army Research Laboratory (ARL) Oak Ridge Associated Universities (ORAU) via a Journeyman Fellowship grant. This work made use of the EPIC facility of Northwestern University's NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. This work also made use of the Center for Hierarchical Materials and Design (CHiMaD under grant No. 70NANB14H012) Metals Processing Facility, and the MatCI Facility which receives support from the MRSEC Program (NSF DMR-1720139) of the Materials Research Center at Northwestern University. The authors acknowledge Suman Bhandari (NU) for assistance with the Bruker Alicona notch measurement and thank Prof. David Dunand (NU), Prof. Gregory Wagner (NU), and Dr. Jon-Erik Mogonye (U.S. Army Research Laboratory, Adelphi) for numerous useful discussions.
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/5
Y1 - 2021/5
N2 - Fractured tensile specimens of INCONEL 718 manufactured via directed energy deposition (DED) with operando thermal metrics and control were heat treated and their mechanical properties were compared as a function of the time spent in the solidification and cooling temperature ranges. Shorter solidification times (faster solidification rates) during the DED process led to higher concentrations of Nb, Al, Mo, and Ti supersaturated in the Fe-Cr-Ni matrix, leading to higher volume fractions of γ’’ strengthening phases and higher hardness after aging (720°/8 h, 620 °C/10 h). This trend persists through hot isostatic pressing (1180 °C at 150 MPa for 4 h), suggesting that secondary treatment processes are not sufficient to fully dissolve detrimental Laves and carbide phases, which initially formed during solidification and affect the alloy's hardness. However, samples with various post-solidus cooling times during the DED process exhibited equivalent hardness after aging, suggesting that the intrinsic heat treatment effect is entirely replaced by the post-processing aging treatment. This study shows that the solidification rate during DED has a lasting effect on the part's mechanical properties, that is not completely mitigated by post-processing treatments, while the initial effects of the post-solidus cooling rate (intrinsic heat treatment) disappear after secondary processes.
AB - Fractured tensile specimens of INCONEL 718 manufactured via directed energy deposition (DED) with operando thermal metrics and control were heat treated and their mechanical properties were compared as a function of the time spent in the solidification and cooling temperature ranges. Shorter solidification times (faster solidification rates) during the DED process led to higher concentrations of Nb, Al, Mo, and Ti supersaturated in the Fe-Cr-Ni matrix, leading to higher volume fractions of γ’’ strengthening phases and higher hardness after aging (720°/8 h, 620 °C/10 h). This trend persists through hot isostatic pressing (1180 °C at 150 MPa for 4 h), suggesting that secondary treatment processes are not sufficient to fully dissolve detrimental Laves and carbide phases, which initially formed during solidification and affect the alloy's hardness. However, samples with various post-solidus cooling times during the DED process exhibited equivalent hardness after aging, suggesting that the intrinsic heat treatment effect is entirely replaced by the post-processing aging treatment. This study shows that the solidification rate during DED has a lasting effect on the part's mechanical properties, that is not completely mitigated by post-processing treatments, while the initial effects of the post-solidus cooling rate (intrinsic heat treatment) disappear after secondary processes.
KW - Directed energy deposition
KW - Hot isostatic pressing
KW - Inconel 718
KW - Solidification rate
KW - Thermal control
UR - http://www.scopus.com/inward/record.url?scp=85099340989&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85099340989&partnerID=8YFLogxK
U2 - 10.1016/j.jmatprotec.2021.117047
DO - 10.1016/j.jmatprotec.2021.117047
M3 - Article
AN - SCOPUS:85099340989
VL - 291
JO - Journal of Materials Processing Technology
JF - Journal of Materials Processing Technology
SN - 0924-0136
M1 - 117047
ER -