Additive Manufacturing: Materials Design and Alloy Development V – Design Fundamentals: High Temperature Alloys
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee, TMS: Integrated Computational Materials Engineering Committee
Program Organizers: Behrang Poorganji, Morf3d; Hunter Martin, HRL Laboratories LLC; James Saal, Citrine Informatics; Jiadong Gong, Questek Innovations LLC; Orlando Rios, University of Tennessee; Atieh Moridi, Cornell University
Wednesday 2:00 PM
March 22, 2023
Room: 24C
Location: SDCC
Session Chair: Jiadong Gong , QuesTek
2:00 PM Cancelled
Bayesian Process Optimization for Porosity Control in Laser-Powder Bed Fusion of IN718 Alloy with Computational Fluid Dynamics Simulation: Peter Morcos1; Dehao Liu2; Alaa Elwany1; Ibrahim Karaman1; Raymundo Arroyave1; 1Texas A&M University; 2Binghamton University
Laser powder bed fusion is an additive manufacturing process where metallic powders are built layer by layer with a high-energy laser beam. It has various applications in aerospace, medical device, and other high-value low-volume manufacturing environments. However, the porosity defects caused by lack of fusion or keyholing have detrimental effects on the mechanical properties of printed parts. Therefore, it is important to optimize process parameters, including laser power and scanning speed, to control porosity and produce defect-free parts. In this work, computational fluid dynamics simulations are used to predict the porosity of printed parts in multi-layer laser powder bed fusion of IN718 alloy. Bayesian optimization is used for process optimization by constructing a Gaussian process-based surrogate model to predict the porosity and sequentially selecting next sampling point for simulation.
2:20 PM
Investigation of Cracking in GRCop42-Inconel 625 Joints: Jakub Preis1; Somayeh Pasebani1; Brian Paul1; 1Oregon State University
GRCop42- Inconel 625 joints have garnered increased attention in recent years due to the high thermal conductivity of the former and high temperature tensile strength of the latter. Such joints, however, suffer from cracking when joined via liquid state processes. In this presentation, mixtures of 15, 30, 50, 70, 75, and 85 wt.% GRCop42 are mixed with Inconel 625 via arc melting and characterized with the goal of unraveling the composition-structure relationship. The results indicate that a liquid miscibility gap exists between a Cu deprived and Cu rich liquid in compositions greater than 20 wt.% GRCop42. For the 30 and 50 wt.% GRCop42 samples, Cu-rich liquid entrapment occurs within the Cu-deprived solid, leading to cracking. For the 70, 75, and 85 wt.% GRCop42 samples, the Cu deprived liquid consolidates and forms a brittle Mo-Nb phase which leads to cracking. The Cu deprived liquid also traps gas, leading to porosity.
2:40 PM
Development of a Gamma-prime-strengthened Ni-base Superalloy for Laser Powder Bed Fusion: Tomonori Kitashima1; Tomoki Hiraga1; Dennis Jodi1; Kyoko Kawagishi1; Masahiko Demura1; Shinya Hibino2; Takayoshi Nakano3; Makoto Watanabe1; 1National Institute for Materials Science; 2Kawasaki Heavy Industries, Ltd.; 3Osaka University
Gamma-prime-strengthened Ni-base superalloys are attractive to apply for additive manufacturing. However, the fabricable conditions of superalloys with a volume fraction of ~30% gamma-prime phase, such as IN738LC, are limited because of solidification cracking that occurs during fabrication. We developed a new Ni-base superalloy that suppressed solidification cracking. That new alloy showed a smaller brittle temperature range (BTR), a volume fraction of ~30% gamma-prime phase, a slower gamma-prime precipitation, and a lower density than IN738LC. Furthermore, high-temperature strength was slightly lower than IN738LC. The systematic data was accumulated to design the new alloy. We performed Scheil solidification simulations using Thermo-Calc software to obtain the BTR and equilibrium gamma-prime volume fraction for more than 30 compositions. JMatPro software was used to estimate density, high-temperature strength, and precipitation rate. Powder was produced by gas atomization. SLM 280HL was used to fabricate specimens, and the properties listed above were evaluated.
3:00 PM
Directed Energy Deposition (DED) of Ni-Al Functionally Integrated Materials (FIMs) via In-situ Alloying with Elemental Ni and Al Powder Feedstocks: Baolong Zheng1; Xin Wang1; Benjamin MacDonald1; Calvin Belcher1; Penghui Cao1; Lorenzo Valdevit1; Enrique Lavernia1; Julie Schoenung1; 1University of California, Irvine
Directed energy deposition (DED) additive manufacturing enables the precise control of composition for the development of functionally integrated materials (FIMs) with site-specific functionality. This compositional control is enabled by the powder injection delivery system that allows for the co-deposition of multiple feedstock powders through individual powder feeders. This process provides a path to rapid development of novel alloys and components with location-dependent properties. In this work, elemental Ni and Al feedstock powders were co-deposited to produce in situ alloyed compositional transitions from Ni to NiAl along the build direction of Ni-NiAl gradient samples. The evolution of microstructure, composition, phases, defects, and mechanical properties were investigated as a function of position in FIMs via experimental characterization and analysis with SEM/EDS, EBSD, XRD, TEM and microhardness mapping. Calculations of the significant exothermic reaction between liquid Ni and Al are used to explain the effective homogeneity in the in situ alloyed FIMs.
3:20 PM Invited
Operando X-ray Diffraction Reveals Solidification Pathway of High Entropy Alloys with Different Degrees of Metastability: Akane Wakai1; Amlan Das2; Atieh Moridi1; 1Cornell University; 2Cornell High Energy Synchrotron Source
High entropy alloys (HEAs) consisting of FeMnCoCr (Fe80-xMnxCo10Cr10 at%, x = 35, 40, and 45) enable a systematic investigation of the effect of phase metastability on the solidification pathway in additive manufacturing (AM). Operando X-ray diffraction conducted at Cornell High Energy Synchrotron Source (CHESS) illuminates the sequence of phase transformations during the rapid solidification inherent to AM. Of the three compositions studied, a metastable martensitic phase is detected only in Fe45Mn35Co10Cr10 (HEA3), which has the lowest stacking fault energy compared to the other two compositions (Fe35Mn45Co10Cr10, HEA1, and Fe40Mn40Co10Cr10, HEA2). The subsequent phase transformation into the stable austenitic phase induces recrystallization, resulting in notable grain refinement and transition to a more equiaxed microstructure in HEA3 compared to HEA1 and HEA2. These findings provide insight into the solidification fundamentals of these HEAs with varying phase metastability and offer us a new tool to engineer the microstructures during AM.
3:50 PM Break
4:10 PM
Understanding the Influence of Boron in Additively Manufactured CoNi-based Superalloys Using Atom Probe Tomography: Qing-Qiang Ren1; Jonathan Poplawsky1; Evan Raeker2; Kira Pusch2; Tresa Pollock2; Stephane Forsik3; Ning Zhiu3; Austin Dicus3; Michael Kirka1; 1Oak Ridge National Laboratory; 2University of California Santa Barbara; 3Carpenter Technology Corporation
Boron is commonly added to superalloys in small amounts to enhance creep resistance, but can lead to cracking at high concentrations, especially during the additive manufacturing process. Two grades of CoNi-based superalloys with different B contents were printed via laser powder bed fusion (LPBF) with the same printing parameters, where only the high B alloy showed serious cracking issues after printing. Atom probe tomography (APT) was used to measure the B concentration within GBs and on cracked surfaces, the results of which relates the B segregation level at GBs and/or cracking surfaces to the nominal compositions. The optimal B level that can offer creep resistance without causing cracking in the superalloys will be discussed based on the obtained results. APT research was supported by the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory.
4:30 PM
Microstructure and Mechanical Properties of Arc Melted NiSi11Cx Alloys: Foysal Kabir Tareq1; Even Wilberg Hovig2; Ragnhild Aune3; Geir Grasmo1; 1University of Agder; 2SINTEF Industry; 3Norwegian University of Science and Technology
Functional materials such as nickel silicides (Ni2Si) are considered promising materials for building complex and strong structures. They have proven to have a high melting point, low electronic resistivity, excellent corrosion resistance, and be thermally stable, however, their overall performances are still challenging due to their brittleness. Therefore, it is essential to prepare high-strength nickel silicide-based materials to improve toughness. In the present work, arc melting has been utilized to synthesize carbon (C) alloyed nickel silicide (NiSi11Cx, x = 0.2, 1 wt%) with varying amounts of carbon with the aim of improving the microstructure and mechanical properties of the alloy. The produced NiSi11Cx alloys were characterized by Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), and microhardness tests. The influence of carbon content on the microstructure and mechanical properties of NiSi20Cx alloys are discussed in this paper.
4:50 PM
Comparing Microstructure and Tensile Properties of Wrought and LP-DED Haynes 233: Effects of Heat Treatment and Test Temperature: Mikyle Paul1; Reza Ghiaasiaan1; Paul Gradl2; Shuai Shao1; Nima Shamsaei1; 1Auburn University; 2NASA Marshall Space Flight Center
This study investigated and compared the microstructure and tensile properties of laser powder directed energy deposited (LP-DED) and wrought Haynes 233. Two heat-treatment (HT) conditions (i.e., solution annealed (SA) and age hardened (AH)) were considered. LP-DED cylindrical rods underwent stress-relieving and hot-isostatic-pressing prior to SA and/or AH. Standard tensile specimens were machined after HT and tested at room temperature and two elevated temperatures. The microstructural evolution during each stage of the HT was characterized using a scanning electron microscope. The dendritic microstructure observed in non-heat-treated LP-DED material was dissolved after HT, forming metal carbides at grain boundaries. Likely due to the abundant carbides formed, recrystallization or grain growth were not observed during HT. Similarly sized γ’ precipitates formed after aging in LP-DED and wrought materials. Tensile results indicated that the LP-DED material in the SA and AH condition was comparable to wrought in the AH condition at all test temperatures.
5:10 PM
Laser Powder Bed Fusion of Defect-Free NiTi Shape Memory Alloy Parts with Superior Mechanical Response: Abdelrahman Elsayed1; Ibrahim Karaman1; Raymundo Arroyave1; Alaa Elwany1; Kadri Can Atli1; Chen Zhang1; Lei Xue1; 1Texas A&M University
Laser powder bed fusion (L-PBF) is a promising additive manufacturing (AM) technique for the fabrication of NiTi shape memory alloy (SMA) parts with complex geometries that are otherwise difficult to fabricate through traditional processing methods. In this study, NiTi parts were fabricated using L-PBF and consistently exhibited room temperature tensile superelasticity up to 6% in the as-printed condition, almost twice the maximum reported value in the literature. The use of optimized processing parameters, carefully tailoring the evaporation of Ni from a Ni-rich NiTi powder feedstock, and controlling the printing chamber oxygen content eliminated porosity and cracks. Crystallographic texture analysis demonstrated that the as-printed NiTi parts had a strong preferential texture for superelasticity. Transmission electron microscopy investigations revealed the presence of nano-sized oxide particles and Ni-rich precipitates in the as-printed parts, which play a role in the improved SE by suppressing inelastic accommodation mechanisms for martensitic transformation.