TY - JOUR
T1 - Improving Productivity in the Laser Powder Bed Fusion of Inconel 718 by Increasing Layer Thickness
T2 - Effects on Mechanical Behavior
AU - Paradise, Paul
AU - Patil, Dhiraj
AU - Van Handel, Nicole
AU - Temes, Samuel
AU - Saxena, Anushree
AU - Bruce, Daniel
AU - Suder, Austin
AU - Clonts, Shawn
AU - Shinde, Mandar
AU - Noe, Cameron
AU - Godfrey, Donald
AU - Hota, Rakesh
AU - Bhate, Dhruv
N1 - Funding Information:
The team would like to thank Honeywell Aerospace Inc. for their support with problem definition, high temperature data and funding that made this work possible. Thanks are also due to Quintus Technologies, North America, for support with Hot Isostatic Pressing (HIP) and to Phoenix Heat Treating for supporting heat treatment of the 300 heat-treated specimens in this work. Additive manufacturing, characterization and testing were all performed at Arizona State University’s Manufacturing Research and Innovation Hub at the Polytechnic School in Mesa, Arizona.
Publisher Copyright:
© 2022, ASM International.
PY - 2022/8
Y1 - 2022/8
N2 - Build time is a critical contributor to overall part cost in the Laser Powder Bed Fusion (L-PBF) process, which in turn plays an important role in whether a part is made with this process or not. While there are many ways to improve productivity in the L-PBF process, this work focuses on one specific approach in the context of L-PBF of Inconel 718: increasing layer thickness, which reduces the number of slices for a given part, but is accompanied with the potential for a degradation in mechanical properties. The study is separated into two parts: the first establishes an optimal process at each of three different layer thicknesses (30, 60 and 80 µm). Having developed an optimum process, the study then obtains density, surface roughness and mechanical property data on specimens fabricated with the selected processes, along with SEM micrographs. Half the specimens are characterized and tested in the as-built condition, the other half go through a heat treatment process that includes Hot Isostatic Pressing (HIP). This study of a total of 600 specimens across six builds confirms that an increase in layer thickness has no significant effect on elastic modulus, but does show reductions in density and strength, along with slight increases in surface roughness. Microstructural studies show no significant differences in grain size and orientation, with a slight increase in carbides and delta precipitates with increasing thickness. Post-heat treatment mechanical strength for all thicknesses is comparable to forged values for Inconel 718, and limited data suggest improvements in excess of forged values can be obtained if specimens are machined prior to testing, with a narrowing of the differences attributable to layer thickness. This study also showed correlations between strength and density and revealed build location dependence for UTS.
AB - Build time is a critical contributor to overall part cost in the Laser Powder Bed Fusion (L-PBF) process, which in turn plays an important role in whether a part is made with this process or not. While there are many ways to improve productivity in the L-PBF process, this work focuses on one specific approach in the context of L-PBF of Inconel 718: increasing layer thickness, which reduces the number of slices for a given part, but is accompanied with the potential for a degradation in mechanical properties. The study is separated into two parts: the first establishes an optimal process at each of three different layer thicknesses (30, 60 and 80 µm). Having developed an optimum process, the study then obtains density, surface roughness and mechanical property data on specimens fabricated with the selected processes, along with SEM micrographs. Half the specimens are characterized and tested in the as-built condition, the other half go through a heat treatment process that includes Hot Isostatic Pressing (HIP). This study of a total of 600 specimens across six builds confirms that an increase in layer thickness has no significant effect on elastic modulus, but does show reductions in density and strength, along with slight increases in surface roughness. Microstructural studies show no significant differences in grain size and orientation, with a slight increase in carbides and delta precipitates with increasing thickness. Post-heat treatment mechanical strength for all thicknesses is comparable to forged values for Inconel 718, and limited data suggest improvements in excess of forged values can be obtained if specimens are machined prior to testing, with a narrowing of the differences attributable to layer thickness. This study also showed correlations between strength and density and revealed build location dependence for UTS.
KW - HIP
KW - Inconel 718
KW - as-printed
KW - build rate
KW - laser powder bed fusion
KW - layer thickness
KW - mechanical properties
KW - productivity
KW - throughput
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U2 - 10.1007/s11665-022-06961-8
DO - 10.1007/s11665-022-06961-8
M3 - Article
AN - SCOPUS:85129592799
SN - 1059-9495
VL - 31
SP - 6205
EP - 6220
JO - Journal of Materials Engineering and Performance
JF - Journal of Materials Engineering and Performance
IS - 8
ER -